Luminous Landscape Forum

Equipment & Techniques => Digital Cameras & Shooting Techniques => Topic started by: Guillermo Luijk on June 25, 2007, 09:07:29 AM

Title: ZERO NOISE technique
Post by: Guillermo Luijk on June 25, 2007, 09:07:29 AM
Find the complete article in English here: ZERO NOISE PHOTOGRAPHY (http://www.guillermoluijk.com/article/nonoise/index_en.htm)

I have tested a technique to completely eliminate noise* on digital images based on the signal/noise ratio improvement achieved through overexposition.
At the same time this technique extremely expands the dynamic range of your image in the shadows (don't think of HDR, it's not like that) and recovers in high detail all textures present in the darkest areas of your image.

* It actually does not eliminate noise at all, just takes for every pixel that one with the best signal to noise ratio. That is why textures are not only 100% preserved, but improved.

To do this you simply need to shoot twice making use of a tripod. One shot will be as usual, keeping highlights unburnt. The second shot with be done with a severe overexposition (I found +4EV to be a good value). A simple piece of software merges those two shoots into one final image with no noise on it and fine detail even in the darkest zones. I have converted my modest 350D in a virtually noise-free digital camera with 12 f-stops of real usable dynamic range.

The development of the technique and results are explained in detail in Spanish here: TECHNIQUE OF THE 4 f-STOPS (http://www.guillermoluijk.com/article/nonoise/index.htm). If I have feedback from the forum I will take some time on a proper translation of the whole article. Meanwhile find here some of the results:

Original shot (the one we would have usually taken, caring of highlights):

(http://www.guillermoluijk.com/article/nonoise/original.jpg)


Second shot (+4EV with respect to previous one):

(http://www.guillermoluijk.com/article/nonoise/sobre.jpg)


Merging result:

(http://www.guillermoluijk.com/article/nonoise/resultado.jpg)


Apparently there is no difference: same tones, bright, contrast. In fact that is what I intended to achieve; unlike HDR programs this method provides a new image with the same appearance as the original one. But let's look closer: first let's analyse the 16-bit histograms:

Original image:
(http://www.guillermoluijk.com/article/nonoise/original_his.gif)

Resulting image:
(http://www.guillermoluijk.com/article/nonoise/resultado_his.gif)

The quality improvement is very noticeable. Histogram is soft and has no zero values as the original had. Non interpolated levels are much closer thanks to overexposition and that means a lot of tonal richness in the definition of textures.

Let's look now at the improvement in some noise samples in the darkest areas (left=original, right=result):

(http://www.guillermoluijk.com/article/nonoise/sillon.jpg)

(http://www.guillermoluijk.com/article/nonoise/dapollito.jpg)

(http://www.guillermoluijk.com/article/nonoise/almohada.jpg)


Where usually there was no more than noise, we have recovered perfectly textures that can now be treated using curves or whatever method you like best. Please note that the original shot was done in ISO100 on a 350D; the reason for such a amount of visible noise is no other than these areas of the image are REALLY very dark; I applied the same curve both to the original and processed images to be able to the check the noise improvement.

This is not an all-purpose technique; first of all we need two expositions what requieres some camera stabilization system (tripod). But I think it can improve a lot quality of results in some applications such as:

   - Architecture and interior design
   - Studio still life
   - Landscapes with dark areas
   - Night or low lighting conditions photography
   - High contrast escenes
   - General photography with zone processing in mind

I plan to develop a program to merge N RAW images (not just 2) with arbitrary expositions (not just 0 and +4EV) to automate the process.

Regards.
Title: ZERO NOISE technique
Post by: Roskav on June 25, 2007, 09:51:06 AM
That looks great ... sounds simple too with just two shots to make the image... I can't believe the final outcome ... both of the shots that you took would have had a certain amount of noise.. but the detail in the final image looks great.. almost if you had been using a fill light.  I would certainly use this for my workflow ... what type of program did you make? Is it similar to a lens cast correction program?

Ros
Title: ZERO NOISE technique
Post by: Guillermo Luijk on June 25, 2007, 10:14:56 AM
Quote
That looks great ... sounds simple too with just two shots to make the image... I can't believe the final outcome ... both of the shots that you took would have had a certain amount of noise.. but the detail in the final image looks great.. almost if you had been using a fill light.  I would certainly use this for my workflow ... what type of program did you make? Is it similar to a lens cast correction program?

Ros
[a href=\"index.php?act=findpost&pid=124764\"][{POST_SNAPBACK}][/a]

I wrote a routine that checks pixel levels in the overexposed image. If the pixel is burnt, I takes it from the other image. If it is not, exposition is corrected and that low noise level is used. It works!

Some more examples:

(http://img512.imageshack.us/img512/6818/resultadohd5.jpg)


Looking at dark areas:

(http://img74.imageshack.us/img74/7854/biciwd5.jpg)

(http://img512.imageshack.us/img512/9699/ruedazh8.jpg)

(http://img265.imageshack.us/img265/1332/sillinef6.jpg)

(http://img526.imageshack.us/img526/6484/bajosyt5.jpg)
Title: ZERO NOISE technique
Post by: BernardLanguillier on June 25, 2007, 10:28:20 AM
If you have a Mac version of your utility, I'd be glad to do some testing for you.

Regards,
Bernard
Title: ZERO NOISE technique
Post by: Ray on June 25, 2007, 11:24:03 AM
GLuijk,
In what way would you say your method is better than standard blending procedures as outlined in this Luminous Landscape tutorial?

http://www.luminous-landscape.com/tutorial...-blending.shtml (http://www.luminous-landscape.com/tutorials/digital-blending.shtml)
Title: ZERO NOISE technique
Post by: madmanchan on June 25, 2007, 11:55:44 AM
Another way to think about this (sort of upside down) is in terms of the expose-to-the-right method discussed here previously. The +4 EV is ETTR. So far, in fact, that the highlights and upper midtones get burned out -- no surprises there. The other image (which has no highlights burnt out) is used to fill in the burnt-out data.
Title: ZERO NOISE technique
Post by: EricV on June 25, 2007, 12:26:22 PM
I have wondered for a long time why film scanners did not use this technique to achieve extremely high dynamic range (or low shadow noise).  They clearly consider this an important specification, since they all inflate it so much in their marketing   Scanners have no stability problem, so aligning multiple exposures should be easy.  This technique would allow a scanner to deliver a merged image with full 16-bit depth, even if the sensor is capable of only 12-bit depth each pass.   Apparently a few scanners are now starting to do this ....
Title: ZERO NOISE technique
Post by: haefnerphoto on June 25, 2007, 12:29:29 PM
I'd certainly like to know more about it.  Please do the translation.  Thanks, Jim
Title: ZERO NOISE technique
Post by: pcrov on June 25, 2007, 12:41:48 PM
Quote
I'd certainly like to know more about it.  Please do the translation.  Thanks, Jim
[a href=\"index.php?act=findpost&pid=124789\"][{POST_SNAPBACK}][/a]

Yes, please do. I'm very interested in this.

Cheers,
Paul
Title: ZERO NOISE technique
Post by: Guillermo Luijk on June 25, 2007, 01:27:42 PM
Quote
GLuijk,
In what way would you say your method is better than standard blending procedures as outlined in this Luminous Landscape tutorial?

http://www.luminous-landscape.com/tutorial...-blending.shtml (http://www.luminous-landscape.com/tutorials/digital-blending.shtml)
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=124781\")

Good question. I have been looking at them, 3 techniques are explained.

First my approach is to provide the same image as the original (no exposition change, no bright change, no contrast change), so that the user can freely use the recovered information in the shades in the way he likes best, but starting from a someway virgin image. Just no noise on it, but expanded dynamic range (I never liked the feeling of HDR techniques).

Secondly, it can work from RAW files, and not only 2 but several of them with any exposition values. With 2 images 12-stops dynamic range is achieved, but with 3 shots 16-stops real dynamic range can be truly achieved with no change in contrast. Allowing change of contrast even more than 16-stops could be obtained, but I think this is too much!

Third is totally automatic, just click a button and wait about 10s for 2 8Mpx RAWs. The result is a 16-bit TIFF file.

Fourth, I plan to offer it for free. If a friend of mine doesn't get to modify the DCRAW source code to perform this algorithm straight into the RAW files before developing them (which would be absolutely fantastic) I will write an application myself. It will read the RAW files but will develop them prior to processing, which is a certain disadvantage compared to my friend's approach.

In fact I already offered a beta simple version for download that takes 2 RAW files with any exposition difference among them and combines into a noise-free output image. Check it here: [a href=\"http://www.macuarium.com/foro/index.php?showtopic=214670&st=25]PROGRAM ZERO NOISE DOWNLOAD[/url]
The program is simple simple, but It's a bit tricky. You will need some Spanish assistance as it works only reading the files from certain folder (c:\ceroruidio\) and needs a DLL to be copied into the PC. I offer there my two dining room RAW files for download and test.
Title: ZERO NOISE technique
Post by: EricV on June 25, 2007, 03:56:27 PM
Can you show us a sample image of a region spanning the bright-dark transition, where your program switches image source pixels?  A good example would be a crop including both the bright lamp and the nearby dark speaker from your first posted image.  If the program has any glitches, that is where they will be found.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on June 25, 2007, 04:03:52 PM
Quote
Can you show us a sample image of a region spanning the bright-dark transition, where your program switches image source pixels?  A good example would be a crop including both the bright lamp and the nearby dark speaker from your first posted image.  If the program has any glitches, that is where they will be found.
[a href=\"index.php?act=findpost&pid=124824\"][{POST_SNAPBACK}][/a]

sure, here it is:

(http://img526.imageshack.us/img526/1641/resultadood4.jpg)

Black areas are taken from the original image while cyan ones are from the +4EV. The election is done pixel by pixel independently, this is the stronghold of automating this method through software as the idea is not new at all.

Another example from a forum member who tested the program:

(http://img452.imageshack.us/img452/1169/comparacionwh0.jpg)

On the left side of:

(http://img452.imageshack.us/img452/7191/resultadoec3.jpg)
Title: ZERO NOISE technique
Post by: timhurst on June 25, 2007, 04:14:44 PM
This result can already be achieved in PS pretty easily using the "blend if" sliders under blending options. Expose one shot for the highlights and one for the shadows, bring the over exposed shot down in the RAW processor so the tonalities are the same, layer the frames in PS and use the blend if tool to reveal the overexposed shot in the shadow regions only to get noise free shadows. As mentioned before the difficult/problematic areas are where there is sensor blooming and fringing.

Does your program offer any advantages to this or is it a similar idea with automation?

tim
Title: ZERO NOISE technique
Post by: Kenneth Sky on June 25, 2007, 04:21:22 PM
Can't this be done in CS 3 Extended by taking multiple exposures on a tripod and merging under Automate? However it won't extend the dynamic range.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on June 25, 2007, 04:31:53 PM
Quote
This result can already be achieved in PS pretty easily using the "blend if" sliders under blending options. Expose one shot for the highlights and one for the shadows, bring the over exposed shot down in the RAW processor so the tonalities are the same, layer the frames in PS and use the blend if tool to reveal the overexposed shot in the shadow regions only to get noise free shadows. As mentioned before the difficult/problematic areas are where there is sensor blooming and fringing.

Does your program offer any advantages to this or is it a similar idea with automation?

tim
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=124830\")

Yeah I pointed that possibility in a forum, as I almost have no idea about PS: select pixels according to their level so those beyond a threshold would be deleted showing the lower layer with the normally exposed image. Could you please try it with my original RAW files? I would be very interested.

[a href=\"http://www.guillermoluijk.com/download/sub.cr2]NORMAL[/url]
OVEREXPOSED (http://www.guillermoluijk.com/download/sobre.cr2)

If you can select individual pixels, then I can only see one more problem: RAW developer are usually non-linear, that means that gamma correction and conversion into a space colour are prior to edition, so as the exposition correction (-4EV) to be applied. I wonder if this can reduce perfomance and quality.
A possible solution would be linerar developing like that achieved with DCRAW (in fact my program calls DCRAW from its code).

Best
Title: ZERO NOISE technique
Post by: Guillermo Luijk on June 25, 2007, 04:38:18 PM
Quote
Can't this be done in CS 3 Extended by taking multiple exposures on a tripod and merging under Automate? However it won't extend the dynamic range.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=124831\")

I must correct this: we trend to call "dynamic range" to those results achieved with HDR software. OK, let's forget for a moment about those tone mapping tools.

Noise is the biggest limitation to record properly detail in the shadows. In this link: [a href=\"http://www.ojodigital.com/foro/showthread.php?t=143407]350D dynamic range[/url] I tested my 350D on a high contrast image and calculated (aprox.) it has a useable dynamic range of 8 f-stops. In the darker shadows noise becomes so noticeable that the 4 lower f-stops that theoretically can be recorded on a 12-bit RAW are unuseable.

But If you clean the noise in those 4 lower f-stops (as this technique does), you are in fact expanding the real dynamic range your camera can record from a scene. I always refer as dynamic range as that of the scene being recorded, not that of my TIFF file. In fact any image with level values from 0 to 65535 should be called as having 16 f-stops of dynamic range, but it is fiction as does not correspond to real scene dynamic range.

If that CS3 option cleans up noise, you can by certain say you are getting more dynamic range.

Check this histogram representation, it's cool: it represents the same escene but shot at 1 f-stop intervals, and representing the true log histogram. As we can see there are 8 f-stops that record properly the scene before noise makes it unusable:

(http://img409.imageshack.us/img409/8467/ejeupss5.gif)
(http://img235.imageshack.us/img235/7214/histologor8.jpg)
(http://img404.imageshack.us/img404/680/ejesag4.gif)

On the right the white wall I was shooting at (it appears green as I developed without applying the white balance that would scale all levels and thus displace the 3 channels).
Title: ZERO NOISE technique
Post by: DiaAzul on June 25, 2007, 05:55:26 PM
Quote
If you have a Mac version of your utility, I'd be glad to do some testing for you.

Regards,
Bernard
[a href=\"index.php?act=findpost&pid=124771\"][{POST_SNAPBACK}][/a]

This technique has been around since...a long time. Though it is good to see it get some airing again.

As well as blending two stacked layers you can also blend multiple bracketed exposures in photoshop using the merge to HDR function (which in CS3 also has the benefit of aligning the layers as well if there is small movement). You have the tools on the Mac already. NB in this case it is not about dramatically expanding the captured dynamic range and more about increasing the quality of what is captured.

The biggest advantage of this method is a reduction in quantisation noise in the shadows resulting from low (12-bit) conversion of analogue to digital signal. This gives much smoother tonality in the shadows and is useful for those who like to manipulate there images. The reduction in shot and thermal noise comes from averaging over multiple exposures (as per traditional correlation processes to remove noise in signal processing).
Title: ZERO NOISE technique
Post by: Guillermo Luijk on June 25, 2007, 06:31:26 PM
Quote
The biggest advantage of this method is a reduction in quantisation noise in the shadows resulting from low (12-bit) conversion of analogue to digital signal. This gives much smoother tonality in the shadows and is useful for those who like to manipulate there images. The reduction in shot and thermal noise comes from averaging over multiple exposures (as per traditional correlation processes to remove noise in signal processing).

yeah but in most medium cameras, quantization problems in the lowest f-stops really don't matter as noise make them absolutely useless.

    0EV: 2048 levels, 2048..4095
   -1EV: 1024 levels, 1024..2047
   -2EV: 512 levels, 512..1023
   -3EV: 256 levels, 256..511
   -4EV: 128 levels, 128..255
   -5EV: 64 levels, 64..127
   -6EV: 32 levels, 32..63
   -7EV: 16 levels, 16..31
   -8EV: 8 levels, 8..15
   -9EV: 4 levels, 4..7
   -10EV: 2 levels, 2..3
   -11EV: 1 level, 1

Last four f-stops are flooded with noise as for instance in the -10EV stop, a noise level of 2 would pull any pixel out of that f-stop.
With this technique no averaging is done, just pixel selection. The equivalent (in the 12-bit range) levels table achieved with a +4EV overexposed image is something like:

    0EV: 2048 levels, 2048..4095
   -1EV: 1024 levels, 1024..2047
   -2EV: 512 levels, 512..1023
   -3EV: 256 levels, 256..511
   -4EV: 2048 levels, 2048..4095
   -5EV: 1024 levels, 1024..2047
   -6EV: 512 levels, 512..1023
   -7EV: 256 levels, 256..511
   -8EV: 128 levels, 128..255
   -9EV: 64 levels, 64..127
   -10EV: 32 levels, 32..63
   -11EV: 16 levels, 16..31


In green are marked those f-stops obtained from the overexposed image. Even in the 12th stop there are levels enough to allow heavy edition. And in addition to this the SNR has improved by a factor of 2^4=16, what makes noise on the 350D practically invisible.

And more than 12 f-stops of real dynamic range is truly possible, thanks to the 12-bit to 16-bit conversion. In fact with an additional +8EV overexposed shot, I am sure that 16 f-stops of dynamic range can be recorded. The difficult part is to find in real life such a huge contrast.
Title: ZERO NOISE technique
Post by: jani on June 25, 2007, 08:25:29 PM
Quote
This result can already be achieved in PS pretty easily using the "blend if" sliders under blending options. Expose one shot for the highlights and one for the shadows, bring the over exposed shot down in the RAW processor so the tonalities are the same,
The emphasized text is the difficult part, at least for the test images provided by Guillermo. At least my meagre skills aren't quite up to matching them well enough to avoid posterization effects.
Title: ZERO NOISE technique
Post by: John Sheehy on June 25, 2007, 09:32:15 PM
Quote
This technique has been around since...a long time. Though it is good to see it get some airing again.[a href=\"index.php?act=findpost&pid=124850\"][{POST_SNAPBACK}][/a]

Mostly with non-linear data, though, which is more unwieldy.

The best place to do most image math is in the RAW linear state where everything is very simple.
Title: ZERO NOISE technique
Post by: bjanes on June 25, 2007, 09:32:53 PM
Quote
I have tested a technique to completely eliminate noise* on digital images based on the signal/noise ratio improvement achieved through overexposition.
At the same time this technique extremely expands the dynamic range of your image in the shadows (don't think of HDR, it's not like that) and recovers in high detail all textures present in the darkest areas of your image.

[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=124758\")

Despite the disclaimer regarding HDR, I'm not sure that the method is that much different from HDR, which is usually used to gain dynamic range, but can also be used to improve shadow detail as explained by Sean McHugh on his Cambridge in Colour website. See the [a href=\"http://www.cambridgeincolour.com/tutorials/high-dynamic-range.htm]Tip[/url] towards the end of the discussion.

Quote
To do this you simply need to shoot twice making use of a tripod. One shot will be as usual, keeping highlights unburnt.

[a href=\"index.php?act=findpost&pid=124758\"][{POST_SNAPBACK}][/a]

Of course, if you are using a tripod, the first thing to try would be to shoot at base ISO and see if that gave decent shadows. If not, then the technique might be helpful, but I'm not sure if HDR techniques already available couldn't also be used.

Anyway, a good idea worth some discussion.

Bill
Title: ZERO NOISE technique
Post by: Ray on June 25, 2007, 10:03:55 PM
The advantage of this method outlined by GLuijk might be the avoidance of halos around bright areas in the scene that one often gets when blending images using layer masks. I'm thinking of situations such as a bright window in a dark room. It's difficult to get an even lighting right to the edge of the window frame.

A method that replaces pixel values rather than averaging them seems likely to  solve this problem.
Title: ZERO NOISE technique
Post by: Gordon Buck on June 25, 2007, 10:14:57 PM
Although I am envious of your mathematical and programming skills, I tinkered a bit with your samples and it seems to me that nearly the same effect can be obtained with CS3 HDR.  I also experimented with Photomatix (plug-in) on the CS3 HDR.

This has been a good lesson for me.  I tend to be a bit heavy handed with Photomatix and HDR (I'm probably not the only one) and this experiment has reminded me that a "non-HDR" image can be produced using the HDR process.

When the goal is a "normal" photo, the noise reduction using "HDR" is very impressive.  

I don't wish to discourage you in the development of what may very well become a new product; however, you must keep in mind that Photoshop and HDR is a competitor.

By the way, I really like the image of the junked bicycles in window light.

Thanks for stimulating a new way of thinking and processing (for me anyway).
Title: ZERO NOISE technique
Post by: Guillermo Luijk on June 26, 2007, 02:02:54 AM
Hi all, you are all right: what I am doing is not far from HDR (or at least from the previous steps any HDR soft performs prior to the tone mapping stage), or to any blending technique of 2 or more images into one as CS3 can do. In fact I posted this method in the Spanish forum calling it "soft HDR". The result of combining different images will, among others, be always an increase in dynamic range through overall signal to noise ratio improvement.

What I try to show you (no commercial interest as I don't sell my little programs (http://www.guillermoluijk.com/software/index.htm)) is a simple soft that is focused on providing:
- Minimum noise (none of the techniques above can improve it; the more can be expected is to match results).
- Maximum texture detail in deep shadows (there is no blending in fact, just pixel selection which is optimum).
- Natural dynamic range expansion in the shadows end (not tone mapping or so steps applied than transfigure our picture's appearance and give it an unreal appearance).

The goal is provide the cleanest possible image to the user with just a click keeping the original image parameters (bright, contrast and tones). It is now up to him to choose the way how to use it; it could even be used as a free of noise input to any HDR soft (Photomatix for instance can deal with one single RAW, or you can use two versions of it for the PS HDR module), or most commonly be processed using zones without surprises when pumping up the darkest areas.

A friend of mine is modifying DCRAW's C source code to perform all these operations, not only in linear as I do, but over the RAW file itself prior to Bayer demosaicing, white balance or any scaling (in fact we are having some trouble with the black point offset most cameras keep in their RAW files that must be substracted before being able to consider a linear behaviour of the sensor, which is not strictly linear due to this offset).
And if he manages, I'll try to convince him to pursue a 16-bit DNG RAW file as an ouptput. That would be simply great, can you imagine? put a bunch of RAW files, with different arbitrary exposition, into a 16-bit RAW file free of noise ready for developing on your favourite RAW developer.
But I have a feeling that recreating the DNG RAW format is not a joke so perhaps we must be happy with just putting our fingers into the image before the developing process.
 
Regards.
Title: ZERO NOISE technique
Post by: DiaAzul on June 26, 2007, 03:31:59 AM
Quote
Mostly with non-linear data, though, which is more unwieldy.

The best place to do most image math is in the RAW linear state where everything is very simple.
[a href=\"index.php?act=findpost&pid=124892\"][{POST_SNAPBACK}][/a]

Fair point - though I was thinking more of the HDR processing which does deal with linear data. It is much harder to blend images after they have a tone curve applied (which is what you are referring to    )
Title: ZERO NOISE technique
Post by: Christopher on June 26, 2007, 06:39:28 AM
Quote
A friend of mine is modifying DCRAW's C source code to perform all these operations, not only in linear as I do, but over the RAW file itself prior to Bayer demosaicing, white balance or any scaling (in fact we are having some trouble with the black point offset most cameras keep in their RAW files that must be substracted before being able to consider a linear behaviour of the sensor, which is not strictly linear due to this offset).
And if he manages, I'll try to convince him to pursue a 16-bit DNG RAW file as an ouptput. That would be simply great, can you imagine? put a bunch of RAW files, with different arbitrary exposition, into a 16-bit RAW file free of noise ready for developing on your favourite RAW developer.
But I have a feeling that recreating the DNG RAW format is not a joke so perhaps we must be happy with just putting our fingers into the image before the developing process.
Regards.
[a href=\"index.php?act=findpost&pid=124921\"][{POST_SNAPBACK}][/a]

If you could manage that, than it would be gigantic. I really would love to use such a thing.  

Now if you can't do that it would use to RAW images to produce a Tiff, right ? Now do we than lose all the things from raw like whitebalance, and other adjustments ?  That would be a drawback for less noise.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on June 26, 2007, 06:50:08 AM
Quote
If you could manage that, than it would be gigantic. I really would love to use such a thing. 

Now if you can't do that it would use to RAW images to produce a Tiff, right ? Now do we than lose all the things from raw like whitebalance, and other adjustments ?  That would be a drawback for less noise.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=124939\")

Yes, but don't worry too much about the white balance. Firstly because the merging tool could let you set the white balance. But another option (that I really like a lot) is to develop my RAWs with DCRAW without white balance applied on them. That optimises the noise reduction algorithm as there is no pre-scaling on any of the RGB channels. If the result of the merge is a linear TIFF the white balance can easily be set with linear curves. I explain exactly this on this [a href=\"http://www.guillermoluijk.com/tutorial/dcraw/index.htm]DCRAW tutorial[/url].
David Coffin, the author of DCRAW, told me it is not recommended to develop RAW files without applying the white balance; however I have found perfect results doing it afterwards. Look at this example:

Image developed without WB:

(http://www.guillermoluijk.com/tutorial/dcraw/anteswb.jpg)


Curves used to apply camera WB (needs the image to be a linear TIFF):

(http://www.guillermoluijk.com/tutorial/dcraw/curvas_wb.gif)


Resulting white balanced image:

(http://www.guillermoluijk.com/tutorial/dcraw/despueswb.jpg)
Title: ZERO NOISE technique
Post by: Gordon Buck on June 26, 2007, 12:00:37 PM
This is really interesting.

I've taken the liberty to post a few CS3 HDR edits on a temporary page of my website, see http://hornerbuck.com/reference.aspx (http://hornerbuck.com/reference.aspx).  

These edits were done very quickly using CS3 and the Photomatix tone map plug-in.
Title: ZERO NOISE technique
Post by: mcbroomf on June 26, 2007, 01:09:44 PM
I don't profess a detailed knowledge of raw development, but isn't Tim Farrar's method the same or similar to what you propose (with a linear TIF output).  
http://www.farrarfocus.com/ffdd/bracket.htm (http://www.farrarfocus.com/ffdd/bracket.htm)

Mike
Title: ZERO NOISE technique
Post by: feppe on June 26, 2007, 02:00:23 PM
This sounds intriguing. While I, too, don't see much difference in the results between this, digital blending and good HDR shots, the fact that it could be automated to a large degree would be a massive improvement over current techniques.

I do a lot of low-light photography (cityscapes mainly) and it's a major pain to get noise/fringe/halo-free images with digital blending using elaborate, blurred and manually adjusted contrast masks and blending modes. I dabbled with HDR but it's just too finicky and doesn't give me reproducible results, at least with my - admittedly limited - HDR skills.

Having a somewhat automatic but customizable program to produce expanded dynamic range images - for lack of a better term - would be heaven-sent. Please keep us posted on any updates!
Title: ZERO NOISE technique
Post by: John Sheehy on June 26, 2007, 02:47:41 PM
Quote
David Coffin, the author of DCRAW, told me it is not recommended to develop RAW files without applying the white balance; however I have found perfect results doing it afterwards. Look at this example:

Image developed without WB:
[a href=\"index.php?act=findpost&pid=124943\"][{POST_SNAPBACK}][/a]

The kind of problems he is talking about probably affect mainly saturated colors of certain hues.  The RGB response of the camera is different than the RGB used in display files and mediums.  RAW converters with optimized color correction need to shift hues and vary saturation, based on hue and saturation of the white-balanced image.  If you don't WB before doing the full conversion, the wrong hues will be shifted and saturation-adjusted after white-balancing.  Some demosaicing algorithms also work with separate luminance and chroma, and these separate differently before and after white balance.
Title: ZERO NOISE technique
Post by: John Sheehy on June 26, 2007, 02:53:32 PM
Quote
Having a somewhat automatic but customizable program to produce expanded dynamic range images - for lack of a better term[a href=\"index.php?act=findpost&pid=125005\"][{POST_SNAPBACK}][/a]

Better terms are definitely needed.  What most people call "HDR" is reall low, compressed DR display of a high DR scene.  Would you call AM Radio "HDR"?  No, but it is quite analogous to what is called "HDR" in digital photography.

A simple linear image with high dynamic range is really only an image with low noise in the shadows; an image in which tones are usable many stops below the maximum signal level.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on June 26, 2007, 03:29:24 PM
Quote
I don't profess a detailed knowledge of raw development, but isn't Tim Farrar's method the same or similar to what you propose (with a linear TIF output). 
http://www.farrarfocus.com/ffdd/bracket.htm (http://www.farrarfocus.com/ffdd/bracket.htm)

Mike
[a href=\"index.php?act=findpost&pid=124992\"][{POST_SNAPBACK}][/a]

yeah! It is exactly the same concept, I am glad to see someone tried it on PS. In fact in my website I pointed this:

"Another method much faster [compared to manual edition] and precise, although I ignore if possible in PS, would be to set in an upper layer the overexposed image and select on it all those individual pixels whose level in any of three channels is beyond some threshold. Done this, these pixels that would represent those burn pixels on any channel would be deleted letting see the corresponding pixels in the lower layer which would come from the correctly exposed shot"

"Otro método mucho más rápido y preciso, aunque ignoro si es realmente posible en PS, sería colocar en la capa superior la imagen sobreexpuesta corregida y seleccionar en ella todos aquellos pixels cuyo nivel en alguno de los tres canales supere cierto umbral. Hecho esto estos píxels que representarían aquellos que quemamos en algún canal, serían borrados dejando ver los píxels equivalentes de la capa inferior que corresponderían a la toma original correctamente expuesta."

I simply automated the trick so the user just needs to select the RAW files and click a button.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on June 26, 2007, 03:33:09 PM
Quote
The kind of problems he is talking about probably affect mainly saturated colors of certain hues.  The RGB response of the camera is different than the RGB used in display files and mediums.  RAW converters with optimized color correction need to shift hues and vary saturation, based on hue and saturation of the white-balanced image.  If you don't WB before doing the full conversion, the wrong hues will be shifted and saturation-adjusted after white-balancing.  Some demosaicing algorithms also work with separate luminance and chroma, and these separate differently before and after white balance.[a href=\"index.php?act=findpost&pid=125010\"][{POST_SNAPBACK}][/a]

I see, so it's a matter of correct tones achieved. Very interesting John.


Quote
Better terms are definitely needed.  What most people call "HDR" is reall low, compressed DR display of a high DR scene.  Would you call AM Radio "HDR"?  No, but it is quite analogous to what is called "HDR" in digital photography.

A simple linear image with high dynamic range is really only an image with low noise in the shadows; an image in which tones are usable many stops below the maximum signal level.

COMPLETELY agree. The problem is that 99% of people think of HDR (which actually just means 'high dynamic range') as tone mapping. That's why I prefer not to enter this battefield and not use the HDR term.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on June 26, 2007, 03:38:26 PM
Quote
I've taken the liberty to post a few CS3 HDR edits on a temporary page of my website, see http://hornerbuck.com/reference.aspx (http://hornerbuck.com/reference.aspx).

Well done gordon, it's the same result. I must confess I never managed to get realistic images from Photomatix that's why I gave up. Surely the Photomatix code did the same as my routine, whenever it was possible it took noise-free pixels from the overexposed image for the ouptput.
Title: ZERO NOISE technique
Post by: Wayne Fox on June 26, 2007, 04:27:55 PM
Very interesting approach ... useful on images that technically fall within the dynamic range of the sensor, but leave noise in the shadow (ie, not really HDR).

Using HDR to accomplish sounds good, but a program that actually works at the pixel level on the raw file would be a great utility.

The links in this thread have helped me understand HDR a little bit better as well.  Thanks.
Title: ZERO NOISE technique
Post by: mkrupp on June 27, 2007, 02:23:31 PM
Wouldn't it be wonderful if they could incorporate the technique right into the camera. i.e.: with one click of the shutter have the camera take two exposures, automatically adjusting the sensitivity for each, and without having the mirror move twice.
Title: ZERO NOISE technique
Post by: Kirk Gittings on June 27, 2007, 03:14:00 PM
Quote
I have wondered for a long time why film scanners did not use this technique to achieve extremely high dynamic range (or low shadow noise).  They clearly consider this an important specification, since they all inflate it so much in their marketing   Scanners have no stability problem, so aligning multiple exposures should be easy.  This technique would allow a scanner to deliver a merged image with full 16-bit depth, even if the sensor is capable of only 12-bit depth each pass.   Apparently a few scanners are now starting to do this ....
[a href=\"index.php?act=findpost&pid=124788\"][{POST_SNAPBACK}][/a]

Two points about this. First the new Silverfast does exactly this by using two scans of different exposure. BUT Sub $1000 flatbed scanners have huge stability problems and great difficulty aligning images. Because of heat expansion and cheap step motors the prosumer flatbeds have difficulty making two scans exactly the same length and there is some loss of resolution though noise is virtually iliminated.
Title: ZERO NOISE technique
Post by: KenS on June 27, 2007, 05:03:42 PM
Quote
Two points about this. First the new Silverfast does exactly this by using two scans of different exposure. BUT Sub $1000 flatbed scanners have huge stability problems and great difficulty aligning images. Because of heat expansion and cheap step motors the prosumer flatbeds have difficulty making two scans exactly the same length and there is some loss of resolution though noise is virtually iliminated.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=125218\")


Kirk,

I was interested in using the Silverfast S/W you refer to with my Minolta Multi Pro (non flatbed) film scanner (6x7 film) until reading about sharpness degradation due to mis-registration.  Here is a reference:

[a href=\"http://tech.groups.yahoo.com/group/multipro/message/2991]http://tech.groups.yahoo.com/group/multipro/message/2991[/url]

I know from experience that the Multi Pro hardware is capable of producing two very similar scans that can be very accurately aligned in Photoshop, so perhaps it is (or was) a Silverfast problem that prevents them from being aligned at scan time ?

Do you know if this problem has been fixed in a newer version of Silverfast?


Ken
Title: ZERO NOISE technique
Post by: Guillermo Luijk on June 27, 2007, 07:14:51 PM
2 more samples. The interest of this case is to check how the algorithm performs in presence of moving scenes (water flowing). As most of the pixels of the river were taken from the overexposed image, the result was not affected.

Real LOG histogram showing this scene was 7.5 f-stops wide. Really a hard shot as the sun was about to set so contrast was severe.

(http://img72.imageshack.us/img72/5505/subhisxu8.gif)


Original:

(http://img243.imageshack.us/img243/4602/origyk9.jpg)


Result:

(http://img243.imageshack.us/img243/3930/resultadolv4.jpg)
Title: ZERO NOISE technique
Post by: EricV on June 27, 2007, 07:59:23 PM
Quote
Two points about this. First the new Silverfast does exactly this by using two scans of different exposure. BUT Sub $1000 flatbed scanners have huge stability problems and great difficulty aligning images. Because of heat expansion and cheap step motors the prosumer flatbeds have difficulty making two scans exactly the same length and there is some loss of resolution though noise is virtually iliminated.
[a href=\"index.php?act=findpost&pid=125218\"][{POST_SNAPBACK}][/a]
Good point.  With a bit more effort, though, the two exposures could be interleaved line-by-line to eliminate alignment problems.  Step to first line position, acquire scan line with short exposure, acquire scan line with long exposure, step to next line position, repeat.  At the end, you have two images with different exposure but perfect alignment, even with a poor stepper.  I don't think anybody actually does this.
Title: ZERO NOISE technique
Post by: jani on June 28, 2007, 07:16:00 AM
Quote
Wouldn't it be wonderful if they could incorporate the technique right into the camera. i.e.: with one click of the shutter have the camera take two exposures, automatically adjusting the sensitivity for each, and without having the mirror move twice.
Some cameras allow exposure bracketing with mirror lock-up and a self-timer, but I'm not aware of any current cameras doing that without releasing and cocking the shutter for each exposure.

The mode you're suggesting seems to have rather few benefits over the use of multiple shutter releases.
Title: ZERO NOISE technique
Post by: digitaldog on June 28, 2007, 09:11:18 AM
Another useful technique is described here:

http://photoshopnews.com/2007/03/27/image-...p-cs3-extended/ (http://photoshopnews.com/2007/03/27/image-stacks-in-photoshop-cs3-extended/)

With the Align Layer's command, you don't need a tripod (if you're careful) and once you use Median on the multiple SO, the noise is greatly reduced.
Title: ZERO NOISE technique
Post by: jani on June 28, 2007, 09:56:12 AM
Quote
Another useful technique is described here:

http://photoshopnews.com/2007/03/27/image-...p-cs3-extended/ (http://photoshopnews.com/2007/03/27/image-stacks-in-photoshop-cs3-extended/)

With the Align Layer's command, you don't need a tripod (if you're careful) and once you use Median on the multiple SO, the noise is greatly reduced.
Hmm, that seems useful, although it seems to require quite a few exposures to achieve that usefulness.

The requirement for the extended version of CS3 is also a bit bothersome; Adobe doesn't appear to provide an upgrade from CS3 to CS3 Extended.
Title: ZERO NOISE technique
Post by: digitaldog on June 28, 2007, 10:00:08 AM
Quote
Hmm, that seems useful, although it seems to require quite a few exposures to achieve that usefulness.
[a href=\"index.php?act=findpost&pid=125409\"][{POST_SNAPBACK}][/a]

Actually in tests I did at the same exposure, the noise reduction was profound!
Title: ZERO NOISE technique
Post by: digitaldog on June 28, 2007, 10:02:32 AM
Quote
The requirement for the extended version of CS3 is also a bit bothersome; Adobe doesn't appear to provide an upgrade from CS3 to CS3 Extended.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=125409\")

There's a back door:

[a href=\"http://photoshopnews.com/2007/05/14/bought-photoshop-but-really-want-extended/]http://photoshopnews.com/2007/05/14/bought...-want-extended/[/url]
Title: ZERO NOISE technique
Post by: MichaelEzra on June 28, 2007, 10:17:38 AM
I am curious if the same result can be achieved in CS2 with layer blending & image calculations applied?
Title: ZERO NOISE technique
Post by: larsrc on June 28, 2007, 10:36:06 AM
Quote
I have tested a technique to completely eliminate noise* on digital images based on the signal/noise ratio improvement achieved through overexposition.
At the same time this technique extremely expands the dynamic range of your image in the shadows (don't think of HDR, it's not like that) and recovers in high detail all textures present in the darkest areas of your image.
[...]
[a href=\"index.php?act=findpost&pid=124758\"][{POST_SNAPBACK}][/a]

A very interesting technique, especially for its simplicity.  Have you compared your results from those delivered by PhotoAcute (http://www.photoacute.com)?  Yes, PhotoAcute can do other things, but the noise reduction is one of the most interesting in it, and it'd be interesting to see if your method can deliver the same.

-Lars
Title: ZERO NOISE technique
Post by: DiaAzul on June 28, 2007, 12:46:58 PM
Quote
A very interesting technique, especially for its simplicity.  Have you compared your results from those delivered by PhotoAcute (http://www.photoacute.com)?  Yes, PhotoAcute can do other things, but the noise reduction is one of the most interesting in it, and it'd be interesting to see if your method can deliver the same.

-Lars
[a href=\"index.php?act=findpost&pid=125418\"][{POST_SNAPBACK}][/a]

Have you got this software to work. I've downloaded the trial and thrown batches of seven bracketed Canon 1DII raw files at it without much success - gets 40 seconds into processing and crashes every time...

Looks very interesting if they can get it to work.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on June 28, 2007, 01:39:54 PM
Quote
A very interesting technique, especially for its simplicity.  Have you compared your results from those delivered by PhotoAcute (http://www.photoacute.com)?  Yes, PhotoAcute can do other things, but the noise reduction is one of the most interesting in it, and it'd be interesting to see if your method can deliver the same.

-Lars

As you say it does a lot of things apart from noise reduction, but regarding this topic I am almost sure it cannot get the same good results as pixel selection. Think that what I do here is to take shots with a very different exposition, so the overexposed version will have much less noise (~2^4=16 times less noise with +4EV second shot) than the other. Nothing can achieve better noise reduction than JUST taking the pixels of the overexposed version whenever possible.
What PhotoAcute does is a different concept: it does not require a difference in exposition among the different shots, it just needs a lot of shots, the more the better. Through some mean or more llikely median filter it achieves noise reduction and other advantages.
Title: ZERO NOISE technique
Post by: Kirk Gittings on June 28, 2007, 02:13:31 PM
I think I was pretty clear that I was not talking about dedicated film scanners. The Minolta is one of the few scanners I have not tried. What I am talking about is a mechanical issue on the flatbeds as it varies depending on the quality and age/usage of the flatbed scanner and varies tremendously depending on whether both scans are done on a warm scanner. One of the ways to defeat the problem is to do a batch scan with a couple of dummy scans up front to warm up the scanners. The latter batch scans register much better. It has become part of my workflow, when I need a high res scan, to do a warm up dummy scan first before the real multi-exposure scan on an Epson 750 or a Microtek 1800f. I have done some limited beta testing with Sf on this issue. If the scans are too far out of wack the software cannot bring it back in, but if they are a little it can handle it-hence the warm up scan. The latest version of SF has extented the "out-of-wack" parameters it can pull back in, but one must work very carefully to take advantage of it. Doing wet scans also helps with registration as there is no issue with the film changing shape from temperature differential. It is similar to having a negative "pop" from the heat as in enlarging resulting in the center of the scan being off register.

Quote
Kirk,

I was interested in using the Silverfast S/W you refer to with my Minolta Multi Pro (non flatbed) film scanner (6x7 film) until reading about sharpness degradation due to mis-registration.  Here is a reference:

http://tech.groups.yahoo.com/group/multipro/message/2991 (http://tech.groups.yahoo.com/group/multipro/message/2991)

I know from experience that the Multi Pro hardware is capable of producing two very similar scans that can be very accurately aligned in Photoshop, so perhaps it is (or was) a Silverfast problem that prevents them from being aligned at scan time ?

Do you know if this problem has been fixed in a newer version of Silverfast?
Ken
[a href=\"index.php?act=findpost&pid=125251\"][{POST_SNAPBACK}][/a]
Title: ZERO NOISE technique
Post by: Roberto Chaves on June 28, 2007, 05:14:54 PM
Quote
Two points about this. First the new Silverfast does exactly this by using two scans of different exposure. BUT Sub $1000 flatbed scanners have huge stability problems and great difficulty aligning images. Because of heat expansion and cheap step motors the prosumer flatbeds have difficulty making two scans exactly the same length and there is some loss of resolution though noise is virtually iliminated.
[a href=\"index.php?act=findpost&pid=125218\"][{POST_SNAPBACK}][/a]

I'm thinking this should be pretty easy to solve on a cheap scanner too. Instead of using the instable step motor to do two scans one could just expose each step twice, then do a step, expose twice, do step etc...
Then the two scans would be interleaved in the same picture which is very easy to separate..
Title: ZERO NOISE technique
Post by: Roberto Chaves on June 28, 2007, 05:16:31 PM
Quote
Good point.  With a bit more effort, though, the two exposures could be interleaved line-by-line to eliminate alignment problems.  Step to first line position, acquire scan line with short exposure, acquire scan line with long exposure, step to next line position, repeat.  At the end, you have two images with different exposure but perfect alignment, even with a poor stepper.  I don't think anybody actually does this.
[a href=\"index.php?act=findpost&pid=125296\"][{POST_SNAPBACK}][/a]

:-) I just wrote the same and now got to read your post..
Title: ZERO NOISE technique
Post by: mkrupp on June 29, 2007, 12:29:51 AM
Quote
Some cameras allow exposure bracketing with mirror lock-up and a self-timer, but I'm not aware of any current cameras doing that without releasing and cocking the shutter for each exposure.

The mode you're suggesting seems to have rather few benefits over the use of multiple shutter releases.
[a href=\"index.php?act=findpost&pid=125380\"][{POST_SNAPBACK}][/a]

The bulk of this thread is about combining multiple exposures,either using PS or using the cool routine developed by GLuijk. My thought is; put the routine in the camera and let its do it all.

I was thinking along the lines of the camera taking bracketed (ISO) exposures and  doing the pixel by pixel selection and replacement using the technique decribed at the start of this thread. Only the final combined image would be saved to the memory card. Perhaps the user would set two ISO's for the exposures. One ISO gets the highlights, the other the shadows. The shutter speed and f stop would have to be the same for each exposure to avoid having wierd things happen to the combined image.

It wouldn't surprise me at all to find out this could be done with nothing more than a firmware update to the camera.
Title: ZERO NOISE technique
Post by: MichaelEzra on June 29, 2007, 06:47:33 AM
Fuji S3 is doing something similar, having 2 interleaved CCD arrays of different sensitivity.
Title: ZERO NOISE technique
Post by: jani on June 29, 2007, 02:53:55 PM
Quote
I was thinking along the lines of the camera taking bracketed (ISO) exposures and  doing the pixel by pixel selection and replacement using the technique decribed at the start of this thread. Only the final combined image would be saved to the memory card. Perhaps the user would set two ISO's for the exposures. One ISO gets the highlights, the other the shadows. The shutter speed and f stop would have to be the same for each exposure to avoid having wierd things happen to the combined image.
I think there will be more "weird things" happening to the combined image from ISO bracketing than shutter speed bracketing.

But yes, this could be an attractive feature to some photographers, though probably not to those who like to shoot in raw.
Title: ZERO NOISE technique
Post by: Jonathan Wienke on July 04, 2007, 08:25:36 AM
Quote
I have tested a technique to completely eliminate noise* on digital images based on the signal/noise ratio improvement achieved through overexposition.
At the same time this technique extremely expands the dynamic range of your image in the shadows (don't think of HDR, it's not like that) and recovers in high detail all textures present in the darkest areas of your image.

* It actually does not eliminate noise at all, just takes for every pixel that one with the best signal to noise ratio. That is why textures are not only 100% preserved, but improved.

To do this you simply need to shoot twice making use of a tripod. One shot will be as usual, keeping highlights unburnt. The second shot with be done with a severe overexposition (I found +4EV to be a good value). A simple piece of software merges those two shoots into one final image with no noise on it and fine detail even in the darkest zones. I have converted my modest 350D in a virtually noise-free digital camera with 12 f-stops of real usable dynamic range.

You are really reinventing the wheel here. Blending together the best parts of frames shot with different exposure levels has been around several years prior to HDR blending being added to Photoshop as a feature. I've been doing so since 2001 or so when I got my first digital camera.

Your technique can be easily duplicated in Photoshop without any special software plugins. Shoot a frame with normal ETTR technique (don't blow the highlights), and a second frame with +3 stops exposure. Process both RAWs with identical settings except for exposure, the second one processed with exposure set to 3 stops below the first. Stack the second exposure on top of the first in Photoshop, with layer blending set as follows:

[attachment=2743:attachment]

Split the two halves of the "This Layer" white slider apart by holding down the ALT key, position them as shown, and you're good to go. This will make luminance values of 220 or above come from the normal exposure, and luminance values of 35 or less to come from the +3 exposure layer. All intermediate luminance values are blended from both layers so there is a smooth transition. Setting the white blend point to 220 keeps saturated colors with clipped channels from contaminating the highlights, and seting the black blend point to 35 keeps the worst of the shadow noise from having any effect at all on the final image. Having a 185-point luminance blend range makes sure that there are no visible seams in the blended image. You can save the layer blend settings as a preset for convenient later use.

I've used this technique successfully for many years.
Title: ZERO NOISE technique
Post by: jani on July 04, 2007, 10:10:47 AM
Quote
I've used this technique successfully for many years.
Unfortunately, it doesn't work well at all with the sample raw files provided by Guillermo Lujik. There are nasty highlight artifacts. Granted, the difference is 4 stops, not 3. Adjusting the sliders so that one gets rid of the highlight artifacts also seems to get rid of the reduced noise.

Care to give it a try, and compare your results with his?

Here's the post with the link to the raw files. (http://luminous-landscape.com/forum/index.php?act=ST&f=4&t=17775#)
Title: ZERO NOISE technique
Post by: Jonathan Wienke on July 04, 2007, 07:21:44 PM
Quote
Unfortunately, it doesn't work well at all with the sample raw files provided by Guillermo Lujik. There are nasty highlight artifacts. Granted, the difference is 4 stops, not 3. Adjusting the sliders so that one gets rid of the highlight artifacts also seems to get rid of the reduced noise.

The post has a link to his article, which has a link to a forum discussion with no RAW links. Post a link direct to the RAWs, so I can find them.

If you're talking about the processed JPEGS, you can't use those because they havent been equalized to matching tonal levels. For my technique to work, you must process one RAW at exposure 0 and the other at exposure -4 (if the shots were bracketed 4 stops apart), otherwise the blended result will look very weird.

The actual exposure settings don't matter, as long as they are the correct interval apart. Given a 4-stop bracket, if the normal exposure is best processed at +0.5EV in ACR, then the other RAW should be processed at -3.5EV. But if the normal exposure is best processed at +0.1EV, then the other RAW should be processed with a -3.9EV exposure setting.
Title: ZERO NOISE technique
Post by: joedevico on July 05, 2007, 12:25:35 AM
Quote
The post has a link to his article, which has a link to a forum discussion with no RAW links. Post a link direct to the RAWs, so I can find them.

They're one the first page of this thread. I'm very interested to see if the same results can be achieved in Photoshop as well. I'm going to try it right now....and it does seem to do a very good job indeed!

jdv
Title: ZERO NOISE technique
Post by: Ray on July 05, 2007, 12:59:46 AM
[attachment=2754:attachment][attachment=2749:attachment][attachment=2750:attachm
ent]
Quote
Unfortunately, it doesn't work well at all with the sample raw files provided by Guillermo Lujik. There are nasty highlight artifacts. Granted, the difference is 4 stops, not 3. Adjusting the sliders so that one gets rid of the highlight artifacts also seems to get rid of the reduced noise.
[a href=\"index.php?act=findpost&pid=126439\"][{POST_SNAPBACK}][/a]

Jani,
Jonathan's method seems to be an improvement over other blending techniques I've come across, but it still relies upon post-blending skills in Photoshop.

I struggle with Photoshop techniques. I know I should spend hours and hours pouring over Photoshop manuals, but for some reason I'm reluctant to do so. Is it a fear of becoming a nerd, or is it just I'm a lazy student who wants the glamour but not the hard yakka? I don't know. A bit of both probably.

I mentioned before, in blending images there's often a halo effect around borders between high contrast transitions. I don't have the skills to get rid of these, at least without painstaking hours of work.

I'm thinking that maybe GLuijk's method offers a quick solution to this.

If you've got the patience, I'll go through a processing procedure I used to blend a couple of images that varied by 4 stops, using Jonathan's method. The final result is not perfect, and not to my complete satisfaction.

The following is a scene of a 5 star hotel 'ensuite' in the foothills of Nepal. (5 stars is relative, you understand   ). The cost for one night in this luxurious accommodation was just US$4. That's less than 1$ per star   . I wanted to capture the scene out of the bathroom window, as well as the bathroom itself.

One shot would simply not do. So I brought my tripod into the bathroom and took a series of 3 bracketed shots.

Here's my attempt at blending 2 of those 3 shots, using Jonathan's method.

(1) The initial blend. Jonathan's recommended settings for "This Layer" should be varied according to the circumstances. It might be right for exposures differences of 3 stops, but my exposures differed by 4 stops, consequently my split layer values were not 35/220, as Jonathan suggested. but 28/43, based upon eyeballing, not mathematical calculation.

[attachment=2749:attachment]

Having flattened the image, I then proceeded to use the limited but familiar techniques I normally use to get the image into shape.

First, a curves application to raise the shadows.

[attachment=2751:attachment]

Then a shadows/highlight adjustment.

[attachment=2753:attachment]

Then a levels adjustment.

[attachment=2754:attachment]

After the levels adjustment (ctrl click on RGB channels, reverse selection, layers levels, 80% opacity), the levels histogram looks like this.

[attachment=2757:attachment]

So here is the rather flat image lacking in umph!

[attachment=2758:attachment]

The problem is; how do I get from this rather flat image to the final vision without introducing artifacts around the edges of the window frames?

[attachment=2759:attachment]
Title: ZERO NOISE technique
Post by: dwdallam on July 05, 2007, 03:57:46 AM
I think what a lot of you are missing here is that this technique is not making an image where you actually see the HDR range increased, but reducing noise in the shadow areas, and bringing back detail, like nothing I've seen, like RAW's "lluminance" etc smoothing, or even PS's "Reduce Noise" filter. I may be wrong, but what hit me is the incredibly clean shadows in what appears to be a a typical dynamic ranged image.

As for automation, just wait. I'm quite sure this will become standard in cameras simply because getting rid of noise is like DUH! No noise is good noise, and if you want noise, then simply switch off advanced noise reduction in camera.
Title: ZERO NOISE technique
Post by: Jonathan Wienke on July 05, 2007, 04:39:03 AM
Quote
The problem is; how do I get from this rather flat image to the final vision without introducing artifacts around the edges of the window frames?

Does this work for you, Ray?
[attachment=2761:attachment]
Title: ZERO NOISE technique
Post by: DiaAzul on July 05, 2007, 04:42:56 AM
Quote
I think what a lot of you are missing here is that this technique is not making an image where you actually see the HDR range increased, but reducing noise in the shadow areas, and bringing back detail, like nothing I've seen, like RAW's "lluminance" etc smoothing, or even PS's "Reduce Noise" filter.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=126537\")

I'm not trying to knock what is being discussed but it really isn't new and has been discussed several times e.g.
[a href=\"http://luminous-landscape.com/forum/index.php?showtopic=3581&hl=]Noise Reduction with multiple exposures[/url]

If you seach through the forums there are examples of using HDR to reduce noise as well as image stacking and we have discussed a number of software packages to reduce noise and increase dynamic range on a number of ocassions.

Quote
I mentioned before, in blending images there's often a halo effect around borders between high contrast transitions. I don't have the skills to get rid of these, at least without painstaking hours of work.


If you have halos around high contrast edges that you need to get rid of then I would suggest shooting multiple exposures no more than 2/3 or 1-stop apart. Blending in Photoshop (and I guess any other technique) will mitigate the effect of halos provided you have sufficient exposures from which to extract 'clean' data. Two exposures 4-stops apart doesn't give sufficient information to eliminate all types of artifacts.
Title: ZERO NOISE technique
Post by: jani on July 05, 2007, 05:31:47 AM
Quote
I'm not trying to knock what is being discussed but it really isn't new and has been discussed several times e.g.
Noise Reduction with multiple exposures (http://luminous-landscape.com/forum/index.php?showtopic=3581&hl=)
Yes, this appears to accomplish with a bunch of exposures what this technique manages with two, and at the cost of more than a little bit of extra manual labour. The exception may be the benefits of the image stack program, which appears to introduce additional flexibility.

For those who don't want to follow links twice, here's a direct link to the PDF (http://users.zoominternet.net/~ed.murphy/stacking.pdf) (1.7 MB).

Quote
If you seach through the forums there are examples of using HDR to reduce noise as well as image stacking and we have discussed a number of software packages to reduce noise and increase dynamic range on a number of ocassions.
From what I've seen and recall, none appear to have the same simplicity as this method.

Quote
If you have halos around high contrast edges that you need to get rid of then I would suggest shooting multiple exposures no more than 2/3 or 1-stop apart.
Why shoot four exposures 2/3 or 1 stop apart, when you can settle for two exposures three or four stops apart?

Quote
Blending in Photoshop (and I guess any other technique) will mitigate the effect of halos provided you have sufficient exposures from which to extract 'clean' data. Two exposures 4-stops apart doesn't give sufficient information to eliminate all types of artifacts.
It seems to work well enough in the examples provided in this thread; I see no artifacts in the images presented to us.

Perhaps more rigorous testing will reveal such artifacts, but so far, Guillermo's method seems better for the sheer simplicity of the procedure.

He's followed the KISS principle.
Title: ZERO NOISE technique
Post by: Ray on July 05, 2007, 05:41:59 AM
Quote
Does this work for you, Ray?
[attachment=2761:attachment]
[a href=\"index.php?act=findpost&pid=126543\"][{POST_SNAPBACK}][/a]

Jonathan,
Not quite, but thanks for the attempt. With that amount of light streaming through the window, the eye would pick up a much brighter scene around the vanity basin. Below is what I'm aiming for. But to achieve this, I had to carefully isolate the scene out of the window with the polygonal lasso tool and process the two parts of the image as though they were separate images. The foliage is perhaps a bit too saturated, but this is the sort of effect I want.

However, in a situation like this, if I have to use the lasso tool, I could simply copy & paste the 'window view' from the dark image to the light image. With both methods I have the problem of that transition edge along the window frame, a problem which is not particularly apparent in the jpeg but is definitely there as can be seen in the crop.

[attachment=2762:attachment]  [attachment=2763:attachment]
Title: ZERO NOISE technique
Post by: Ray on July 05, 2007, 05:54:46 AM
Quote
Two exposures 4-stops apart doesn't give sufficient information to eliminate all types of artifacts.
[a href=\"index.php?act=findpost&pid=126545\"][{POST_SNAPBACK}][/a]

David,
This is perhaps the appeal of GLuijk's method, when fully developed. Two exposures 4 stops apart should contain all the data one needs.
Title: ZERO NOISE technique
Post by: Jonathan Wienke on July 05, 2007, 07:20:36 AM
Quote
However, in a situation like this, if I have to use the lasso tool, I could simply copy & paste the 'window view' from the dark image to the light image. With both methods I have the problem of that transition edge along the window frame, a problem which is not particularly apparent in the jpeg but is definitely there as can be seen in the crop.

Here's a way to fix your edge blending problem:

1. Have the window view and interior in separate layers, with window view layer on top.

2. Create a layer mask for the window view layer.

3. Assign the original window view exposure (where the room view is very dark) to the layer mask.

4. Do a level adjustment on the layer mask to make it straight black and white with no intermediate values, so that the window view is 100% white and the room view is 100% black. Depending on image content, you may need to do a bit of paintbrushing to eliminate stray specks where they don't belong. The Dust & Scratches filter can be handy for this, but must be used very carefully.

5. Do a 2-pixel Gaussian blur on the layer mask to make the transition soft and fuzzy. The edge will look horrible, but don't panic, there's a method to the madness.

6. Do another Levels adjustment on the layer mask. By adjusting the source white and black point sliders, you will be able to move the outer and inner edges of the blend transition zone independently anywhere within the 2-pixel blur zone, which will avoid matte lines and make the blend as seamless and natural-looking as possible.

Whenever you're compositing images, you always should have a bit of fuzziness at the edge where one layer transitions to another, or you'll either have matte lines or an artificial "cut-out" look to the edge. This technique makes it easy to get natural-looking blends along composited edges.
Title: ZERO NOISE technique
Post by: Ray on July 05, 2007, 09:06:28 AM
Quote
Whenever you're compositing images, you always should have a bit of fuzziness at the edge where one layer transitions to another, or you'll either have matte lines or an artificial "cut-out" look to the edge. This technique makes it easy to get natural-looking blends along composited edges.

Yes, I realise this. It's really an issue of how much stuffing around one needs to do to achieve the right balance which looks natural. However, I'll try to go through those procedures you've outlined tomorrow with a clear head.

I noticed that the CS3 demo version had a feature whereby one can enlarge or diminish a selection by a specified number of pixels, as well as specifying a degree of feathering. That could be useful with this particular image.

Out of curiosity, I loaded the 3 RAW bracketed images of this scene into CS2's HDR. The results are at least equally useful. There are many ways to get a desired result. I used a bit of dodge and burn along the window edges. It's probably not an ideal image to demonstrate the halo problem because I see signs of clear silicon sealant that have smeared the edges of the window panes   .

[attachment=2764:attachment]
Title: ZERO NOISE technique
Post by: Jonathan Wienke on July 05, 2007, 02:13:18 PM
Quote
Yes, I realise this. It's really an issue of how much stuffing around one needs to do to achieve the right balance which looks natural. However, I'll try to go through those procedures you've outlined tomorrow with a clear head.

I noticed that the CS3 demo version had a feature whereby one can enlarge or diminish a selection by a specified number of pixels, as well as specifying a degree of feathering. That could be useful with this particular image.

The advantage to my technique is that it allows one to expand or contract the selection, as well as adjust feathering amount of the blend, with a real-time preview.

I noticed the sealant on the window as well. The small upper section of window visible seems to be free of it though.

On a different note, I spent a few hours playing around with some bracketed triples 3 stops apart, experimenting with various blending techniques. I discovered that using all 3 images works best. Blending the +3 and -3 shots only leaves somewhat of a quality gap where the highlights and shadows look good, but the midtones are noisy, and the transition between the highlight shot and the shadow shot is uglier. The comparison crops have all had the same sharpening:

2 frame blend: (+3 and -3 only)
[attachment=2766:attachment]

3 frame blend: (+3, 0, and -3)
[attachment=2767:attachment]

As you can see, the highlights and shadows look equally good (as they should, coming from the same frames), but the midtones of the 2-frame blend are much noisier.

The attached ZIP file has the layer styles I used to blend the frames. For the 2-frame blend, the -3 frame was on the bottom as background, and the +3 frame was on top with the "HDR Shadow Layer Blend" style applied. For the 3-frame blend, the 0 frame was background, then the -3 frame with the "HDR Highlight Layer Blend (3 Frame)" style applied, then the +3 frame with the "HDR Shadow Layer Blend (3 Frame)" style applied. After flattening both, I picked a crop area that had samples of the entire tonal range, cropped, and applied equal sharpening to both.

To use the blend styles, simply unzip and then load the extracted file from the Styles palette in PS. Process all 3 RAWs exactly the same except for the exposure setting. The 0 file is your best guide for things like setting white balance, lens corrections, etc.; try to adjust exposure of the 0 file so that shadows and highlights are about equally clipped. If you only want to improve tonality within a single-frame exposure range, be strict about setting the exposure of the -3 file exactly 3 stops above the 0 file setting, and the +3 file exactly 3 stops below. But if you want to include more DR in the frame (which will of course make it look flatter after blending and require more curves and local contrast boosting), adjust the -3 file for the best highlight appearance (no or only light specular clipping) and the +3 file for best shadow appearance (no or only light specular shadow clipping). Then stack the layers 0 (background), +3 / HDR Highlight Layer Blend (3 Frame), -3 HDR Shadow Layer Blend (3 Frame).

Enjoy!
Title: ZERO NOISE technique
Post by: Alaska on July 05, 2007, 05:26:41 PM
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The attached ZIP file has the layer styles

The ZIP file downloads as "index.php".  Did get it to work by renaming to "index.zip".  Then it would unzip to HDR Blend States ASL.

Thanks for the great hints......

Jim
Title: ZERO NOISE technique
Post by: Guillermo Luijk on July 06, 2007, 05:15:34 PM
Yeahh! we did it! a mate of me and me have modified DCRAW's source code to implement this technique as an extra option. And it works great!!! it has some advantages over the little test program I provided here, as it works straight from the RAW files. I mean it does the image blending before the RAW developing stage and that has many important advantages:

1. Noise free virtual RAW: Bayer interpolation is done over a 16-bit "virtual" RAW where noise has already been minimised. This way we avoid noise propagation into interpolated cells.
2. Process previous to white balance: WB rescales all channels, so the threshold value for the blending algorithm had to be chosen for the most severely corrected channel. Now an optimal threshold is chosen for the three channels at a time as WB has not been applied yet.
3. Only one RAW development: thanks to the internal virtual RAW data generated, no matter how many files are to be blended, only one RAW developing will take place incresing calculation speed.

For those familiar to DCRAW the miX option will be something like:
dcraw -X [threshold] [exposure correction] ... *.cr2 for instance
It will take all indicated RAW files, calculate their relative exposition no matter which it is, and blend them into an optimum noise free image with the same appearance (contrast and tone) as the original but with expanded dynamic range in the shadows and zero noise.
As people are not used to DCRAW perhaps I will write a simple GUI for this tool.


Hi Jonathan Wienke, just to say that I never stated that reducing noise through multiexposure was a new idea; I am sorry if it looked like that. In particular in my website I textually say: "Las ideas descritas hasta ahora no son nuevas, la novedad consiste en aplicarlas con el fin de obtener una reducción de ruido radical y de forma automatizada (...)", that means "The ideas described here [referring to the noise reduction process through overexposition] are not new, the new thing consists of applying them with the goal of achieving a radical noise reduction in an automated way".

If you can get the same noise reduction as this modifed DCRAW with PS, at the same speed (about 10s to process 3 shots starting from their RAW files), and with the same ease of use (one button click), just let me know. Otherwise you are invited to try our tool.
Apart from the advantages of RAW blending commented at the begining, a progressive blending technique as the one you propose in PS is not optimal (nor needed) compared to a more simple but effective pixel selection algorithm for two reasons: first your noise reduction is not maximised as you are mixing noisy pixels with noise-free pixels, while I simply discard the first ones. Secondly, even minimal image overlap errors (less than 1 pixel) would lead to a loss of sharpness due to averaging in your case.


I did a test yesterday over a high contrast scene (about 13 f-stops of real dynamic range) and achieved a completely free of noise histogram with texture recovery in the darkest shadows:
(please note these histograms are logaritmic plots where each vertical division corresponds to 2 image f-stops. The original hardly achieved to represent properly 8 f-stops due mainly to noise and quantization. The blended version clearly increases the histogram precision up to 13 f-stops):

(http://img515.imageshack.us/img515/5434/todosqi5.gif)

(http://img62.imageshack.us/img62/7476/resultado90ru7.jpg)
[span style=\'font-size:8pt;line-height:100%\'](what can be seen on the floor is not noise but the tiles texture)[/span]


Please find here the RAW files of my two test images for anyone wanting to try alternative techniques:

Couch:
http://www.guillermoluijk.com/download/sub.cr2 (http://www.guillermoluijk.com/download/sub.cr2)
http://www.guillermoluijk.com/download/sobre.cr2 (http://www.guillermoluijk.com/download/sub.cr2)

Blue room:
http://www.guillermoluijk.com/download/foto1.cr2 (http://www.guillermoluijk.com/download/foto1.cr2)
http://www.guillermoluijk.com/download/foto2.cr2 (http://www.guillermoluijk.com/download/foto2.cr2)
http://www.guillermoluijk.com/download/foto3.cr2 (http://www.guillermoluijk.com/download/foto3.cr2)
Title: ZERO NOISE technique
Post by: pcrov on July 06, 2007, 06:11:29 PM
That's fantastic!

I'm not familiar with DCRAW but don't mind working on the command line. Is there somewhere I can download your version? Will this be able to output a DNG file?
Title: ZERO NOISE technique
Post by: Guillermo Luijk on July 06, 2007, 06:23:18 PM
Quote
I'm not familiar with DCRAW but don't mind working on the command line. Is there somewhere I can download your version? Will this be able to output a DNG file?[a href=\"index.php?act=findpost&pid=126905\"][{POST_SNAPBACK}][/a]

it's still not ready, coming soon.

we were thinking about that, to produce a 16-bit DNG as an output. Would be orgasmic (lol). But need to know a lot about RAW file formats. Perhaps with assistance from David Coffin...
Title: ZERO NOISE technique
Post by: digitaldog on July 06, 2007, 06:26:32 PM
Quote
we were thinking about that, to produce a 16-bit DNG as an output. Would be orgasmic (lol). But need to know a lot about RAW file formats. Perhaps with assistance from David Coffin...
[a href=\"index.php?act=findpost&pid=126909\"][{POST_SNAPBACK}][/a]

Well DNG would be a quite welcomed feature!
Title: ZERO NOISE technique
Post by: Roberto Chaves on July 07, 2007, 04:40:57 AM
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Well DNG would be a quite welcomed feature!
[a href=\"index.php?act=findpost&pid=126910\"][{POST_SNAPBACK}][/a]

I second that!
Title: ZERO NOISE technique
Post by: Jonathan Wienke on July 07, 2007, 05:48:38 AM
Quote
Hi Jonathan Wienke, just to say that I never stated that reducing noise through multiexposure was a new idea; I am sorry if it looked like that. In particular in my website I textually say: "Las ideas descritas hasta ahora no son nuevas, la novedad consiste en aplicarlas con el fin de obtener una reducción de ruido radical y de forma automatizada (...)", that means "The ideas described here [referring to the noise reduction process through overexposition] are not new, the new thing consists of applying them with the goal of achieving a radical noise reduction in an automated way".
My Spanish is very limited, so I wasn't able to read your web site article. My apologies. The first program you posted about breaks no new ground, and offers little or no advantage over blending techniques that have been available for years, including the method I posted about using layer blend styles.

On the other hand, your DCRaw modification is very interesting and is something new, DR blending the linear RAW data prior to other processing. This approach is much better than blending after gamma adjustment and tone curves have been applied.

If you can create a tool with a GUI that can take 3 RAWs exposed at 3-stop intervals, blend them, and output a blended 16-bit DNG that ACR or any other DNG-aware program can process the same as the original RAW, I'd happily buy it. It would need to meet the following criteria:

1. The highlights would need to be set so that the brightest value in the darkest image is scaled automatically to the maximum usable value in the output file without clipping.

2. The output DNG must process identically to the original RAW. This means that the normal ACR color processing must work identically to an original RAW. I've color calibrated ACR to my cameras, and would not want to get different color when processing a blended DNG than when processing a single RAW. ACR would have to recognize the camera model and serial number from the DNG file for this to work. The complete DNG file format specification is available from Adobe, so this shouldn't be too difficult. The hardest part would be figuring out what shutter speed to put in the metadata when the file is derived from several exposures with different shutter speeds.

3. Some means to manually adjust registration between the RAWs would be necessary, expecially if it could be done in 1/2-pixel increments. This would require that Bayer interpolation be done prior to blending. The output file would have to be a linear-RGB DNG, but ACR's normal color processing would not be affected. Limiting output to 16-bit linear RGB would greatly simplify your work; you'd only have one output format to worry about. It is just tagged with the appropriate camera model, serial number, and other metadata. DCRaw can handle the plethora of input formats, so you wouldn't have to re-invent the wheel for that side.

If the Bayer interpolation routine was modified so that it took all source images into account simultaneously, slight mis-registration would actually be an advantage, because there would be more than one color channel at each output pixel site. Imagine that when shooting, the +3 exposure was shifted 1 pixel vertically relative to the 0 exposure, and the -3 exposure was shifted 1 pixel horizontally relative to the 0 exposure. After registering the RAW data, the Bayer interpolation now has 2 color channels per pixel to use, either red and green, or green and blue. The exposure scaling would have to be accounted for, but increased color accuracy could be achieved. Some medium format digital backs do this (but not at different exposure levels) to improve color accuracy; 3 exposures are taken, whith the sensor being moved 1 pixel vertically or horizontally between frames.

You can download the complete DNG specification from a link at the bottom of this page (http://www.adobe.com/products/dng/).

Edit: The Bayer interpolation modification wouldn't really be necessary, the color accuracy improvement happens already when the different exposures are blended together. Never mind.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on July 07, 2007, 08:15:55 AM
Quote
If the Bayer interpolation routine was modified so that it took all source images into account simultaneously, slight mis-registration would actually be an advantage, because there would be more than one color channel at each output pixel site. Imagine that when shooting, the +3 exposure was shifted 1 pixel vertically relative to the 0 exposure, and the -3 exposure was shifted 1 pixel horizontally relative to the 0 exposure. After registering the RAW data, the Bayer interpolation now has 2 color channels per pixel to use, either red and green, or green and blue. The exposure scaling would have to be accounted for, but increased color accuracy could be achieved. Some medium format digital backs do this (but not at different exposure levels) to improve color accuracy; 3 exposures are taken, whith the sensor being moved 1 pixel vertically or horizontally between frames.

You can download the complete DNG specification from a link at the bottom of this page (http://www.adobe.com/products/dng/).

Edit: The Bayer interpolation modification wouldn't really be necessary, the color accuracy improvement happens already when the different exposures are blended together. Never mind.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=126968\")

The program I already posted blends the images prior to any gamma correction, as DCRAW is a linear RAW converter (if used in -4 mode, and I did). The improvement of this new DCRAW version is that the blending is applied even before the white balance, which improves even more the accuracy of the threshold set and in addition to this saves some RAW developings. We can say it's more elegant.
This is a comparision between the results of:
1. My previous program and a conservative threshold decision value: still noise on some areas (wall).
2. My previous program and an agressive threshold decision value: noise is almost gone but incorrect colour pixels appear (couch).
3. Modified DCRAW with a conservative threshold decision value: noise is almost gone and more regularly spreaded, and no colour artifacts.

(http://img487.imageshack.us/img487/1073/3muestrasmk5.jpg)


We don't sell software. All we do if for free and for fun. It's not likely that we will achieve the DNG output as it's an effort beyond our intentions, and we love DCRAW! so we trust it. DCRAW is a really VERY good RAW developer itself. But I will check your links to find out, thank you.


"1. The highlights would need to be set so that the brightest value in the darkest image is scaled automatically to the maximum usable value in the output file without clipping."

This requirement would be fine in theory. In practice it is not so much, and the reason is that the least exposed imaged provided to the program is taken as a reference for the output. The improvement of scaling it so it fits the maximum (65535 level) is not worth as almost ALL valid images have some pixels close to blow or directly burnt (this is the usual case). You can use this program of mine: [a href=\"http://www.guillermoluijk.com/software/histogrammar/index.htm]Histogrammar[/url] that plots 16-bit histograms to check this by yourself on any of your images. If you wait a couple of days, I have developed a new version of Histogrammar which reads directly image files (the one currently in the link needs some mess with a PS plugin and translates the image into a text file. horrible but I didn't have the libraries needed to read 16-bit images) and even plots logaritmic histograms like the one I showed before.
However we will introduce an exposure correction parameter into this DCRAW, so that: dcraw -X 4.0 ... *.cr2 for instance will correct by 2 f-stops up (2^2=4.0) the resulting image avoiding level agregation and mathematical rounding errors if that would be done afterwards.

Moreover the white balance can be very agressive. A scaling of more than one complete f-stop in some channel is very usual and this burns pixels; but few of them. So it is strange to find an image that can strictly be exposed up as most of them have something burnt (and if they don't have, is because were heavily underexposed).
The important thing is to have a good exposure gap between the least and the most exposed images. This really fulls with detail all the shadows thanks to the 12-bit to 16-bit conversion. These images can handle really severe toning curves before showing any banding or posterization.
Our program calculates itself the relative exposures between images without looking at the metadata; and handles N images with N from 2 to what your memory can store, taking always for each individual pixel the best possible value from the whole set of images provided. In fact, this relative exposure calculation is more accurate than using the EV values set in the camera since lighting conditions could vary slightly during the shots (for instance a cloud passing by).

Thanks for taking your time, we will let you know when this DCRAW is ready.
Title: ZERO NOISE technique
Post by: Jonathan Wienke on July 07, 2007, 04:48:56 PM
I've been working with sets of 3 images exposed 3 stops apart, +3, 0 and -3. The -3 image usually doesn't have any clipped pixels unless there is a light source in the image, like a bare light bulb or something really shiny with bright specular highlights. Blending these images together with exposure set to -2, 0, and +2 gives a slightly flat-looking initial result, but which still responds well to curves and local contrast enhancement so that you get nice smooth transitions to clipped highlights and shadows, and end up with about 2 stops more DR in the image as well as practically no noise throughout the tonal range.

So I'd like to be able to boost that -3 image to max values below clipping, and scale everything else below that. I'm not talking about changing the WB settings in the RAW, scale all channels by the same amount so the most exposed channel maxes out at 65535 and everything else scales proportionately. When you add 6 stops to the 7 stops or so that most cameras can capture well in a single exposure, using all of the 16-bit linear scale is not a bad idea, especially given that the blue channel can be 2 stops or more below the red channel in incandescent and similar lighting. That means the deepest shadows in the blue channel can be 15 stops below the highlights in the red channel, and an unused stop of highlight room can mean the difference between whether that shadow detail is processed meaningfully or gets posterized into oblivion.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on July 07, 2007, 05:40:06 PM
oh I understand now. Your way to proceed is to bracket a couple of stops below and above the "correct" exposure. In my opinion bracketing underexposed as a rule is not necesarry. Any underexposed shot (and -3 is VERY underexposed) doesn't provide additional clean information to the 0 and +3 shots.

My concept here is slightly different: take one shot making sure that you capture all highlights, but not underexposing at all, just make sure you don't blow information (a RGB splitted camera histogram is good enough to check this). This is the most important shot of all and after it you can forget about any additional underexposed shot.
If the camera has punctual measuring (don't know if this is the right term in English), the classical trick is measure the highlights and overexpose that measure by over +2EV according to the camera particular metering behaviour.
Afterwards comes the funny part: additional shots with RADICAL overexposures. 2, 3, 4 f-stops... The only care that has to be taken is not exceed a 4 f-stops gap between every two shots or some areas could start to suffer quantization problems or at least not reach the degree of tonal richness we are expecting from the whole image.

For the example of the couch I used:
0 EV, +4 EV
For the example of the blue room I used:
0 EV, +3 EV, +6 EV

Taking this last example I simply made sure not to burn pixels in the 0 EV (in fact I have just analysed and got real {696;501;344} RGB burnt levels which is absolutely nothing in a 8 Mpx sensor. Those few pixels surely were on the ceiling lightbulb.
And I didn't use 0, +4, +8 because a crowd came to the scene and I could not keep on shooting; but 0,+4,+8 would have been desirable for a better recovery in the 13th stop (see histogram).

It works.

In your case, I am sure with -3,0,+3 you will achieve a fantastic noise reduction and DR enhancement in the shadows, but I am not so sure if the DR  in your image clearly represents the DR found in the scene. I mean: my shots are blended and developed in linear mode, and then obviously comes the conversion to the colour profile (sRGB, AdobeRGB,...) that will introduce a non linear gamma correction that is unavoidable. But I feel comfortable to know that right the previous step to this is pure linear data where 1 stop of DR exactly corresponds to 1 stop of DR in the scene since the sensor is workig in its linear range. I think you have more control this way on what's going on with your image than in a PS blending.
Title: ZERO NOISE technique
Post by: Ray on July 08, 2007, 10:45:57 PM
Quote
oh I understand now. Your way to proceed is to bracket a couple of stops below and above the "correct" exposure. In my opinion bracketing underexposed as a rule is not necesarry. Any underexposed shot (and -3 is VERY underexposed) doesn't provide additional clean information to the 0 and +3 shots.

My concept here is slightly different: take one shot making sure that you capture all highlights, but not underexposing at all, just make sure you don't blow information (a RGB splitted camera histogram is good enough to check this). This is the most important shot of all and after it you can forget about any additional underexposed shot.
[a href=\"index.php?act=findpost&pid=127035\"][{POST_SNAPBACK}][/a]

I've spent several hours over the past few days comparing Jonathan's 'split top layer blending method' with 2, 3 and 4 RAW images of the same scene loaded into HDR

The 'split top layer' method using just 2 images does not need an underexposed image. The bottom layer should just be an image correctly exposed for the highlights, which usually means when converting in ACR, approximately a minus 1 stop EC adjustment should be applied to 'recover' highlights.

My initial impression was that I was still getting a hint of the halo effect, but I now believe this was due to traces of silicon sealant around the edges of the window panes and/or inappropriate adjustments with Photoshop's Shadow/Highlight tool.

What I have noticed is that HDR in PSCS2 is not able to recover highlights well. If the lowest exposure is a full exposure to the right, the highlights will be slightly blown. In order to avoid this, I think it's necessary to include an underexposed image when using HDR.

Loading 16 bit TIF conversions into HDR seems to produce some pretty awful results.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on July 09, 2007, 02:29:06 AM
Quote
I've spent several hours over the past few days comparing Jonathan's 'split top layer blending method' with 2, 3 and 4 RAW images of the same scene loaded into HDR

The 'split top layer' method using just 2 images does not need an underexposed image. The bottom layer should just be an image correctly exposed for the highlights, which usually means when converting in ACR, approximately a minus 1 stop EC adjustment should be applied to 'recover' highlights.

My initial impression was that I was still getting a hint of the halo effect, but I now believe this was due to traces of silicon sealant around the edges of the window panes and/or inappropriate adjustments with Photoshop's Shadow/Highlight tool.

What I have noticed is that HDR in PSCS2 is not able to recover highlights well. If the lowest exposure is a full exposure to the right, the highlights will be slightly blown. In order to avoid this, I think it's necessary to include an underexposed image when using HDR.

Loading 16 bit TIF conversions into HDR seems to produce some pretty awful results.
[a href=\"index.php?act=findpost&pid=127206\"][{POST_SNAPBACK}][/a]

May I have your RAW files to test them with my routine?

Some people have come to me with different HDR programs (like Photomatix) and after fiddling some time with them achieved similar results to pixel selection for blending. But usually HDR's tone mapping enforces local microcontrast keeping low the overall contrast, and this provides very unreal results; it's simply a different concept. I prefer not to alter local nor overall contrast and let the user the task to get the best from the noise free image in the way he likes best (contrast curves, zone edition, even HDR on other sofware,...).
Title: ZERO NOISE technique
Post by: Ray on July 09, 2007, 09:03:37 AM
Quote
May I have your RAW files to test them with my routine?

Some people have come to me with different HDR programs (like Photomatix) and after fiddling some time with them achieved similar results to pixel selection for blending. But usually HDR's tone mapping enforces local microcontrast keeping low the overall contrast, and this provides very unreal results; it's simply a different concept. I prefer not to alter local nor overall contrast and let the user the task to get the best from the noise free image in the way he likes best (contrast curves, zone edition, even HDR on other sofware,...).
[a href=\"index.php?act=findpost&pid=127226\"][{POST_SNAPBACK}][/a]

Sending the files right now. Hope my connection is not interrupted. In the meantime, here's the comparison between an HDR result and the lowest exposure converted in ACR with minus 1 EC.

These are actually 'print screen' crops of 200% enlargements. No processing has been done except adjusting the WB slider in the HDR shot for maximum highlight recovery.

[attachment=2782:attachment]

ps. Sorry about that water pipe in front of the view. It's manadatory in Nepal to always obstruct a fine view, if possible. Fortunately, there are still lots of pristine views they have not got around to spoiling yet   .
Title: ZERO NOISE technique
Post by: vjbelle on July 09, 2007, 05:43:27 PM
Quote
Hmm, that seems useful, although it seems to require quite a few exposures to achieve that usefulness.

The requirement for the extended version of CS3 is also a bit bothersome; Adobe doesn't appear to provide an upgrade from CS3 to CS3 Extended.
[a href=\"index.php?act=findpost&pid=125409\"][{POST_SNAPBACK}][/a]
jani,

There is an upgrade path from CS3 to CS3 Extended.  I did just that today and I was way outside of the 30 day exchange time period.  It is important that your original purchase of CS3 was in fact an upgrade from an earlier PS release and not a purchase of the retail program.  Adobe sales is not completely familiar with this program but customer support aided me with their internal documentation that allows a customer who upgraded to CS3 and then would like to upgrade to CS3 extended the opportunity to receive full credit for their purchase and pay just the difference for CS3 Extended.  Contact customer support and they should be able to guide you through the process.

Hope this helps.....  

Victor
Title: ZERO NOISE technique
Post by: Erick Boileau on July 11, 2007, 10:58:21 AM
GLuijk   I like very much your concept to work directly in the RAW
I am using blending options since a long time  , or photomatix, but to do that directly in the RAW wil be the best
Title: ZERO NOISE technique
Post by: MichaelEzra on July 16, 2007, 01:58:20 PM
GLuijk,

When do you plan to release the new version of the program? It is very interesting!

Thanks,
Title: ZERO NOISE technique
Post by: Wayne Fox on July 19, 2007, 11:26:53 PM
Quote
You are really reinventing the wheel here. Blending together the best parts of frames shot with different exposure levels has been around several years prior to HDR blending being added to Photoshop as a feature. I've been doing so since 2001 or so when I got my first digital camera.

In a way, yes, but in a way no.  What is normally talked about is blending multiple exposures to extend dynamic range.

This seems more of a technique to use 2 exposures of a scene that falls within the dynamic range of the sensor but pushes it to the limit to reduce noise in the shadow areas.

Granted the way to accomplish this is virtually identical.  Just most of us wouldn't bother doing this if our histogram shows we aren't clipping either shadows and highlights.

It has given me some food for thought however, and I can see now there are times doing this may be useful even if I'm not after an HDR image.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on July 22, 2007, 10:31:54 PM
I tested this technique as a regular technique in a photographic indoor session last week, but in high constrast scenes as windows opened outdoor. The result has been very good: easy shooting (just regular shot plus one +4EV additional shot for every scene), easy edition (just a curve on which I set a mask not to blow windows facing outside), and natural result with no noise and expanded dynamic range.

Find here some examples (Canon EOS 350D + Canon 10-22 and a really bad tripod):


(http://img261.imageshack.us/img261/5217/recreo180kbyq7.jpg)


(http://img264.imageshack.us/img264/4453/sala180kbkn2.jpg)


(http://img182.imageshack.us/img182/7760/meetingfz1.jpg)


(http://img182.imageshack.us/img182/7616/recepcion180kbsb6.jpg)


(http://img410.imageshack.us/img410/8751/despacho180kbee3.jpg)



Taking the first scene: the 350D is too noisy to record outdoor highlights and indoor texture detail in a single shot. This happened when trying: highlights blown if texture is kept (picture left), texture is gone if highlights are kept (picture right):

(http://www.guillermoluijk.com/article/nonoise/ejemplo1.jpg)

Blending result:

(http://www.guillermoluijk.com/article/nonoise/ejemplo2.jpg)
Title: ZERO NOISE technique
Post by: haefnerphoto on July 22, 2007, 10:43:49 PM
What did you do to blend the exposures?  You mentioned a mask, how did you make it?  Jim
Title: ZERO NOISE technique
Post by: Guillermo Luijk on July 22, 2007, 11:06:18 PM
Quote
What did you do to blend the exposures?  You mentioned a mask, how did you make it?  Jim
[a href=\"index.php?act=findpost&pid=129457\"][{POST_SNAPBACK}][/a]

I used a little program I wrote to automate it, the download site must be somewhere in this thread.
The mask was just in the edition stage, to preserve the windows from blowing.
Title: ZERO NOISE technique
Post by: button on July 23, 2007, 10:23:58 PM
Quote
GLuijk,

When do you plan to release the new version of the program? It is very interesting!

Yes, please let us know when the GUI version is available.  Your work is outstanding!

John
Title: ZERO NOISE technique
Post by: Ray on July 24, 2007, 02:34:18 AM
Indeed! Your interiors are very esthetic, GLuijk. Sorry I haven't got around to sorting it out with my ISP about the errors I get when I try to send you 12mb file files.

I should (could) be on broadband, but I object to signing a 24 month contract when I intend travelling a lot in the near future.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on July 25, 2007, 02:44:27 PM
Quote
I should (could) be on broadband, but I object to signing a 24 month contract when I intend travelling a lot in the near future.
[a href=\"index.php?act=findpost&pid=129651\"][{POST_SNAPBACK}][/a]


why don't you put your raw files on a pendrive and try someone else's fast connection?
Title: ZERO NOISE technique
Post by: MichaelEzra on July 25, 2007, 04:55:01 PM
GLuijk,

my complements to your work on this new tool.

I am curious, whether you adjust the alignment of images while merging them together? There is "HDR alignment tool" which can curently do that, and probably  could be used to provide input files to your program, yet not in the RAW format...

If you need any help with specific RAW files, I can offer Fuji S3 and Mamiya ZD files for testing.

Please let me know,

Thanks,
Title: ZERO NOISE technique
Post by: Guillermo Luijk on August 08, 2007, 06:54:14 AM
Hi, for all those that could be interested, I have just uploaded an English version of the article explaining this technique: ZERO NOISE PHOTOGRAPHY (http://www.guillermoluijk.com/article/nonoise/index_en.htm)

Hopefully I will write a final version of the program ready to use along this month (Aug 2007).

Regards
Title: ZERO NOISE technique
Post by: Caracalla on August 08, 2007, 07:12:53 AM
Quote
Hi, for all those that could be interested, I have just uploaded an English version of the article explaining this technique: ZERO NOISE PHOTOGRAPHY (http://www.guillermoluijk.com/article/nonoise/index_en.htm)

Hopefully I will write a final version of the program ready to use along this month (Aug 2007).

Regards
[a href=\"index.php?act=findpost&pid=132099\"][{POST_SNAPBACK}][/a]

[span style=\'font-size:14pt;line-height:100%\']Amazing tool[/span]

Looking forward to it!!!
Thanks
Title: ZERO NOISE technique
Post by: feppe on August 08, 2007, 12:10:03 PM
Quote
Hi, for all those that could be interested, I have just uploaded an English version of the article explaining this technique: ZERO NOISE PHOTOGRAPHY (http://www.guillermoluijk.com/article/nonoise/index_en.htm)

Hopefully I will write a final version of the program ready to use along this month (Aug 2007).

Regards
[a href=\"index.php?act=findpost&pid=132099\"][{POST_SNAPBACK}][/a]

Thanks! The latest examples you provide are most impressive, no haloing or artificial/painterly look usually connected to "true" HDR images. I look forward to your program!
Title: ZERO NOISE technique
Post by: MichaelEzra on August 20, 2007, 02:43:21 PM
Any update on this?
Title: ZERO NOISE technique
Post by: Quentin on August 21, 2007, 12:12:33 PM
Quote
Any update on this?
[a href=\"index.php?act=findpost&pid=134367\"][{POST_SNAPBACK}][/a]

Looks great.  Charge a reasonable fee for a decent GUI based Windows program and I'll pay up  

Quentin
Title: ZERO NOISE technique
Post by: julian_love on August 22, 2007, 08:44:13 AM
Quote
Looks great.  Charge a reasonable fee for a decent GUI based Windows program and I'll pay up   

Quentin
[a href=\"index.php?act=findpost&pid=134540\"][{POST_SNAPBACK}][/a]


Me too, for a Mac version.

Julian
Title: ZERO NOISE technique
Post by: Caracalla on August 22, 2007, 10:21:54 AM
Quote
Looks great.  Charge a reasonable fee for a decent GUI based Windows program and I'll pay up   

Quentin
[a href=\"index.php?act=findpost&pid=134540\"][{POST_SNAPBACK}][/a]


Me too, [span style=\'font-size:14pt;line-height:100%\']   Mac [/span]version    

Cheers
Title: ZERO NOISE technique
Post by: Natasa Stojsic on August 23, 2007, 04:40:42 AM
Quote
Looks great.  Charge a reasonable fee for a decent GUI based Windows program and I'll pay up   

Quentin
[a href=\"index.php?act=findpost&pid=134540\"][{POST_SNAPBACK}][/a]


Me too, for a Mac version.
Title: ZERO NOISE technique
Post by: urbanpicasso on August 23, 2007, 06:02:13 AM
Im in......windows  

davidbogdan





Quote
Me too, for a Mac version.
[a href=\"index.php?act=findpost&pid=134992\"][{POST_SNAPBACK}][/a]
Title: ZERO NOISE technique
Post by: Christopher on August 23, 2007, 08:21:28 AM
Quote
Im in......windows  

davidbogdan
[a href=\"index.php?act=findpost&pid=134997\"][{POST_SNAPBACK}][/a]

Screw the mac and give us windows ;-)
Title: ZERO NOISE technique
Post by: MichaelEzra on August 23, 2007, 08:53:00 AM
windows;)
Title: ZERO NOISE technique
Post by: Kika Livno on August 23, 2007, 03:32:30 PM
I belive it is logical to do it for both, WINDOWS & MAC
Title: ZERO NOISE technique
Post by: feppe on August 23, 2007, 03:55:07 PM
Quote
I belive it is logical to do it for both, WINDOWS & MAC
[a href=\"index.php?act=findpost&pid=135101\"][{POST_SNAPBACK}][/a]

But, but, then we wouldn't have pages and pages of illuminating "write a Mac version of it plsohpls I'll give you my first born son!"
Title: ZERO NOISE technique
Post by: Guillermo Luijk on August 24, 2007, 06:55:41 AM
Hey, I don't have a Mac, and I have no idea how Macs are programmed. If anyone is interested, I will let him know about the blending algorithm to implement a Mac version.

Sorry!
Title: ZERO NOISE technique
Post by: larsrc on August 26, 2007, 07:13:11 AM
I work on Linux.  You were talking about integrating it in dcraw?  How did that pan out?
Title: ZERO NOISE technique
Post by: MichaelEzra on September 05, 2007, 10:16:46 AM
Any update on this program?
Title: ZERO NOISE technique
Post by: Guillermo Luijk on September 07, 2007, 01:50:31 PM
Quote
Any update on this program?
[a href=\"index.php?act=findpost&pid=137467\"][{POST_SNAPBACK}][/a]

I have already thought of how to implement all the algorithms, and now I have come to the user interface. It will consist of 5 stages:

1. RAW development
2. Image Alignment
3. Relative Exposure calculation
4. Advanced features (blend thresholds, anti ghost, progressive blending)
5. Blending

These stages have to be calculated in a sequence and we can perform them all at a time or just up to the currently selected option. And we can change parameters and repeat the process only from a specific point, not having to repeat the calculation of previous stages.

However I want to keep it simple for non advanced users, so there will be a "Do it all" button that will use default parameters to get the resulting image at a mouse click. Advanced features can be learnt in a progressive way.

If you have any suggestions this is the time!
(I am sorry Mac users, I don't have a Mac, and I don't know how to program your beautiful machine).

(http://img248.imageshack.us/img248/8377/dibujogf8.jpg)
Title: ZERO NOISE technique
Post by: feppe on September 07, 2007, 04:42:12 PM
Wow, I'm glad to see the development is quite far already. Good work!

My suggestion is to make the final image a layer so it can be easily blended with the originals. It would also be nice to have any mask layers retained for manual tweaking, like PhotoKit Sharpener does.

I can't wait to try this out!
Title: ZERO NOISE technique
Post by: tived on September 08, 2007, 12:29:42 AM
GLuijk,

it looks very good to me! So I would expect that there would be a cost involved? and when will it be available?


great work there - very impressive

Henrik
Title: ZERO NOISE technique
Post by: MichaelEzra on September 09, 2007, 11:22:55 AM
GLuijk,

Thanks for the update! From what I understand from your post, it is wonderful:)
Please let me know if you need any help with beta testing.
Title: ZERO NOISE technique
Post by: larsrc on September 09, 2007, 11:39:22 AM
Quote
I have already thought of how to implement all the algorithms, and now I have come to the user interface. It will consist of 5 stages:

1. RAW development
2. Image Alignment
3. Relative Exposure calculation
4. Advanced features (blend thresholds, anti ghost, progressive blending)
5. Blending

These stages have to be calculated in a sequence and we can perform them all at a time or just up to the currently selected option. And we can change parameters and repeat the process only from a specific point, not having to repeat the calculation of previous stages.

However I want to keep it simple for non advanced users, so there will be a "Do it all" button that will use default parameters to get the resulting image at a mouse click. Advanced features can be learnt in a progressive way.

If you have any suggestions this is the time!
(I am sorry Mac users, I don't have a Mac, and I don't know how to program your beautiful machine).

(http://img248.imageshack.us/img248/8377/dibujogf8.jpg)
[a href=\"index.php?act=findpost&pid=137923\"][{POST_SNAPBACK}][/a]

Looks pretty, but in this case the proof is definitely in the eating.

As for the Mac users (and me Linux user):  What are you using for a graphics toolkit?  If you used QT, it'd be autoportable to Mac and Linux.

If that's not an option, are you going to release the source so somebody else could have a go at a port?

-Lars
Title: ZERO NOISE technique
Post by: Guillermo Luijk on September 09, 2007, 11:56:25 AM
Quote
Looks pretty, but in this case the proof is definitely in the eating.

As for the Mac users (and me Linux user):  What are you using for a graphics toolkit?  If you used QT, it'd be autoportable to Mac and Linux.

If that's not an option, are you going to release the source so somebody else could have a go at a port?

-Lars
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=138192\")


mmm I am using the [a href=\"http://perso.orange.fr/pierre.g/xnview/engfl.html]Gfl SDK[/url] 16-bit graphic library by a French guy called Pierre E. Gougelet. It's a C library but he provides a VB6 API so I can call its functions from my code. In fact I just need to be able to read/write image files and read/write pixel channels in 16 bit. It was hard to come to a library that can just do that.

I am not sure whether I will set the source code for download, still have to think about it.

What's the meaning of 'the proof is definitely in the eating'? hehe it's the first time I hear about that expression.

Regards.
Title: ZERO NOISE technique
Post by: John Hollenberg on September 09, 2007, 01:01:12 PM
Quote
What's the meaning of 'the proof is definitely in the eating'? hehe it's the first time I hear about that expression.

[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=138197\")

The actual quote is "the proof of the pudding is in the eating", quoted in Don Quixote by Miguel Cervantes.  Means that "Actual use is the best test":

[a href=\"http://bartelby.com/59/3/proofofthepu.html]http://bartelby.com/59/3/proofofthepu.html[/url]

--John
Title: ZERO NOISE technique
Post by: jani on September 10, 2007, 04:03:31 AM
Quote
mmm I am using the Gfl SDK (http://perso.orange.fr/pierre.g/xnview/engfl.html) 16-bit graphic library by a French guy called Pierre E. Gougelet. It's a C library but he provides a VB6 API so I can call its functions from my code. In fact I just need to be able to read/write image files and read/write pixel channels in 16 bit. It was hard to come to a library that can just do that.
Ah, well, since it's in Visual Basic 6, the program won't be portable, that's a shame.

But perhaps some enterprising person can -- as you suggested earlier -- take the algorithms and make an independent, portable implementation.
Title: ZERO NOISE technique
Post by: pobrien3 on September 10, 2007, 04:36:21 AM
Isn't it enough that Guillermo is very generously and graciously sharing and writing this for free (BTW Guillermo, I'll also happily pay for it - you should be rewarded for your work) that we also have to have people complaining that he's not writing a Mac version, or asking him to make his source code freely available??

Load Bootcamp and use that.  If I was writing this product and I saw this response to my efforts, then I'd keep it to myself.  But then I'm not as nice or as generous a person as Guillermo ...
Title: ZERO NOISE technique
Post by: Christopher on September 10, 2007, 05:49:15 AM
Quote
Isn't it enough that Guillermo is very generously and graciously sharing and writing this for free (BTW Guillermo, I'll also happily pay for it - you should be rewarded for your work) that we also have to have people complaining that he's not writing a Mac version, or asking him to make his source code freely available??

Load Bootcamp and use that.  If I was writing this product and I saw this response to my efforts, then I'd keep it to myself.  But then I'm not as nice or as generous a person as Guillermo ...
[a href=\"index.php?act=findpost&pid=138349\"][{POST_SNAPBACK}][/a]


dito.
Title: ZERO NOISE technique
Post by: dwdallam on September 16, 2007, 04:11:22 AM
I would suggest making this program Open Source unless you want some company ripping it off and reprogramming it in C++Turbo or something. Then we WILL be paying for it. Also, if you make it Open Source, people will work on it indefinitely and it can never be sold--ever. Either that or Copyright it ASAP.
Title: ZERO NOISE technique
Post by: feppe on September 16, 2007, 05:29:40 AM
Quote
I would suggest making this program Open Source unless you want some company ripping it off and reprogramming it in C++Turbo or something. Then we WILL be paying for it. Also, if you make it Open Source, people will work on it indefinitely and it can never be sold--ever. Either that or Copyright it ASAP.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=139709\")

I don't see how open sourcing it would make it any less likely that someone will rip it off.

And the program is copyrighted automatically, just like photos, manuscripts, etc. In the US you need to register it to sue for punitive damages AFAIK, but Guillermo is not based in the US.

Nevertheless, if he won't be charging money for it, I'd also like to see it licensed under one of the [a href=\"http://creativecommons.org/]Creative Commons licenses[/url]. I use the Attribution license for all my photography on my website, with the aim of encouraging people to use and distribute it as much as they can, while retaining copyright and getting credited. Creative Commons also has commercial-friendly licenses which allow charging for the program under certain circumstances.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on September 16, 2007, 10:30:29 AM
Well, I am using DCRAW to develop the RAW files and Xnview libraries to read/write pixel values, so the only think it's really mine is the idea to put all that together and make it work to blend images.

However I think I have in mind some nice algorithms to eliminate ghosting and visible borders with local progressive blending, as well as producing high quality B&W images doing all calculations (exposure correction, B&W channel mixing and even gamma) in floating point precision before the final 16-bit rounding is applied.

I have been very lazy these last weeks, today is a nice afternoon in Madrid to devote to some coding.

I would like to show some results soon.

Thanks for the interest.
Regards.
Title: ZERO NOISE technique
Post by: jani on September 16, 2007, 06:30:45 PM
Quote
Isn't it enough that Guillermo is very generously and graciously sharing and writing this for free (BTW Guillermo, I'll also happily pay for it - you should be rewarded for your work) that we also have to have people complaining that he's not writing a Mac version, or asking him to make his source code freely available??
Hey, cool down a bit, you don't have to be quite that hostile and fanatic about your dislike for everything non-Windows and open source, especially when I've suggested no such thing.

I did, however lament that he'd locked himself to a very specific platform -- one that's not even future proof for Windows!

Guillermo has previously suggested that he'd release the algorithms used, so that others could implement the solution, and if he does that, it would be much appreciated.

Quote
Load Bootcamp and use that.
:roll:

Quote
If I was writing this product and I saw this response to my efforts, then I'd keep it to myself.
If you were the author of the program and posted such a response, you'd definitely get to keep it to yourself; very few people want to use software made by people with such hostile attitudes, because they simply don't want to be treated that way.

Quote
But then I'm not as nice or as generous a person as Guillermo ...
You certainly aren't.

Guillermo has been both nice and generous, and I hope he continues to be so, regardless of how he chooses to make his software available. His attitudes has also shown that he's responsive and friendly when people make suggestions for improvements and changes.

Yes, a small fee for the software and/or services would probably be appropriate.
Title: ZERO NOISE technique
Post by: jani on September 16, 2007, 06:40:22 PM
Quote
Well, I am using DCRAW to develop the RAW files and Xnview libraries to read/write pixel values, so the only think it's really mine is the idea to put all that together and make it work to blend images.
In the US, those ideas are probably still possible to patent.

Quote
However I think I have in mind some nice algorithms to eliminate ghosting and visible borders with local progressive blending, as well as producing high quality B&W images doing all calculations (exposure correction, B&W channel mixing and even gamma) in floating point precision before the final 16-bit rounding is applied.
It will be interesting to see (yet another) demonstration of your results!

Keep it up!
Title: ZERO NOISE technique
Post by: pobrien3 on September 16, 2007, 10:19:25 PM
Jan, just because my post followed yours (I didn't quote yours either) doesn't mean my remarks were addressed solely to you: they were addressed to all those who when offered something for free were ungrateful and wanted more.  Just for the record, I too am a Mac user.  I also use a PC at those times when I can't get appropriate software for the Mac, and vice versa.  Bootcamp too difficult to use, too inconvenient?  I use it, it works fine: it's not perfect, but life's like that.  I have a hammer in my toolbox, but I also have a screwdriver - I don't use just one of them for all jobs.  Buggers my workflow when I have to switch from one to the other though...  

And I'm so glad you won't use software that's not written by nice people (I trust you got a full character reference of all the Apple and Adobe developers by the way).

Peter
Title: ZERO NOISE technique
Post by: Natasa Stojsic on September 22, 2007, 01:56:55 PM
Guillermo Luijk,

When is your beautiful Software due for release?

I hope soon
Title: ZERO NOISE technique
Post by: jani on September 22, 2007, 03:54:04 PM
Quote
Just for the record, I too am a Mac user.  I also use a PC at those times when I can't get appropriate software for the Mac, and vice versa.  Bootcamp too difficult to use, too inconvenient?  I use it, it works fine: it's not perfect, but life's like that.
 - again

1) PowerMacs/PowerBooks can't use Bootcamp to load Windows.
2) Not everybody runs a compatible version of Windows anyway, and VB6 isn't guaranteed support in future Windows versions.
3) Not everybody wants to hand money to Bill Gates.
4) And even so, not all of the world is Mac + Windows.

But none of these items are really problematic if the algorithms are free for others to implement.
Title: ZERO NOISE technique
Post by: StuT on September 23, 2007, 05:25:05 PM
Not wishing to exacerbate things but, could Vmware or an equivalent product not be a solution for those not running Windows? It is not perfect but it would allow a version of windows to be run for Linux certainly - I'm not a Mac person but I think this works.

I have used it in the past for friends who have programs which only run under Windows 95 or Windows 98 and they still need access to the program (the backwards compatibility of XP or 2000 is insufficient). So perhaps VB 6 could be handled in a similar manner.

I would love to have the ability to run some programs which only run on a Mac on my PC in a VM if Mr Jobs would allow me to  

Stu
Title: ZERO NOISE technique
Post by: sergio on September 25, 2007, 04:18:23 PM
Your stuff sounds very interesting. I'll keep an eye on this thread to see when you have it ready.

Sergio
Title: ZERO NOISE technique
Post by: Quentin on September 25, 2007, 05:30:35 PM
My Chequebook / Paypal account is ready the moment the program goes on sale - can I assume raw conversion within the program is not essential, or if it is, then Mamiya ZD files will be supported?  

Quentin
Title: ZERO NOISE technique
Post by: julian_love on September 26, 2007, 03:29:16 AM
Quote
My Chequebook / Paypal account is ready the moment the program goes on sale
[a href=\"index.php?act=findpost&pid=141818\"][{POST_SNAPBACK}][/a]


Me too - I'd pay $50 for a Mac version with a decent GUI.

Julian
Title: ZERO NOISE technique
Post by: Guillermo Luijk on September 26, 2007, 07:41:25 PM
Quote
My Chequebook / Paypal account is ready the moment the program goes on sale - can I assume raw conversion within the program is not essential, or if it is, then Mamiya ZD files will be supported?   

Quentin
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=141818\")

Well, I have found that many people don't feel comfortable with the idea of any program developing their RAW files. I can understand it perfectly, you are used to some tools and workflow, and don't want to change.

However a very important point to make all algorithm and calculations easy is that images are in their primitive linear state; while all commercial RAW developers generate gamma corrected and usually colour profiled images.

[a href=\"http://www.guillermoluijk.com/tutorial/dcraw/index_en.htm]DCRAW[/url] is a very good RAW developer, and supports an always increasing (till his author David Coffin decides to stop updating; that will be a sad day) list of cameras; including your Mamiya.
Find a list here: FORMATS SUPPORTED BY DCRAW (http://cybercom.net/~dcoffin/dcraw/index.html#cameras)

In addition to this, no matter if you used 2 or 10 shots for the same scene, all of them will be quickly developed and their relative exposures accurately calculated (not read from EXIF), and this can be done thanks to having total control of the development process. So not having to develop the images by yourself avoids errors and saves time.

Some people asked for a 16-bit DNG output that could be later developed on any RAW developer of your own. I think this is a great idea but, at least at the moment, far of my intentions and skills.

However I am planning to introduce a tonal richness quality increase and a virtually unlimited DR expansion (16 f-stops or more is definitively possible) thanks to the introduction of the gamma correction performed in floating point precission, prior to one only 16-bit final integer rounding. In a 16-bit linear RAW no more than ~12 f-stops can be coded with a reasonable tonal richness due to the lack of levels in the lowest f-stops.
The difficult part will be to find in the real world a scene with such a huge dynamic range!

PS: BTW Quentin, I looked through your portfolio and your images are oustanding! do you think you really need this tool? lol
Title: ZERO NOISE technique
Post by: cmi on September 26, 2007, 07:50:05 PM
This is my first post in this forum, I have to say I registered because of this thread. A very nice program! I hope it isnt too late to make a suggestion, I would like to have command-line support if possible. Would be awesome ^^

All the best

Christian
Title: ZERO NOISE technique
Post by: laughfta on September 26, 2007, 09:44:29 PM
Guillermo, congratulations on your new program! (I'm sure there will be many more to come, too!)
Title: ZERO NOISE technique
Post by: thierrylegros396 on September 27, 2007, 03:35:55 AM
Quote
However I am planning to introduce a tonal richness quality increase and a virtually unlimited DR expansion (16 f-stops or more is definitively possible) thanks to the introduction of the gamma correction performed in floating point precission, prior to one only 16-bit final integer rounding. In a 16-bit linear RAW no more than ~12 f-stops can be coded with a reasonable tonal richness due to the lack of levels in the lowest f-stops.
The difficult part will be to find in the real world a scene with such a huge dynamic range!

Not sure that such a big compression will give a good picture in a screen or worse in a paper.
I've seen so many awfull HDR pictures, partly because authors wanted to show everything in the picture, even in very dark areas !
Keep in mind that our eyes have also an "instantaneous limited dynamic range" !
So, a good idea will be creating an "S-shape" to preserve dynamic and to keep good contrast in the the "mid-tones" !

But I'm very impressed by your work and results !!

Thierry
Title: ZERO NOISE technique
Post by: Guillermo Luijk on September 27, 2007, 08:09:53 AM
Quote
Not sure that such a big compression will give a good picture in a screen or worse in a paper.
I've seen so many awfull HDR pictures, partly because authors wanted to show everything in the picture, even in very dark areas !
Keep in mind that our eyes have also an "instantaneous limited dynamic range" !
So, a good idea will be creating an "S-shape" to preserve dynamic and to keep good contrast in the the "mid-tones" !

But I'm very impressed by your work and results !!

Thierry
[a href=\"index.php?act=findpost&pid=142159\"][{POST_SNAPBACK}][/a]


well most HDR images which look awful, actually don't look that way for being HDR (in fact many of them are not even really high DR), but because their author abused of the tone mapping process which yiedls very unrealistic results if not properly used.

My program is not going to apply any tone mapping. What I do is much simpler, just an image CONTAINING all the information spreaded along many f-stops. It will be up to the user to choose the way how to make use of it. Curves can be applied, so as even tone mapping if your HDR software allows a single TIFF as input.
These huge DR images I am talking about, will be something more interesting from a scientific point of view, that from a practical. In fact, a single S curve applied on to a large DR image (let's say 13 f-stops or more) to show all the available DR will produce a flat (poor in contrast) and boring image. But I want to try it anyway.


PS: thx Gloria!
Title: ZERO NOISE technique
Post by: MichaelEzra on September 27, 2007, 08:17:27 AM
GLuijk,

if you could also add a superresolution algorithm to ths program, this will be priceless.
There is a program PhotoAcute (photoacute.com) it works, but only on small images, it cannot be used for high end photography.

I started this post: http://luminous-landscape.com/forum/index....showtopic=19860 (http://luminous-landscape.com/forum/index.php?showtopic=19860)
(Multishot superresolution software) as I am looking for a solution to digitize my 6x7 negatives using Mamiya ZD, yet at a higher resolution than the sensor can record. PhotoAcute can create higher resolution images due to sub-pixel misalignment of the originals, it also cleans noise as you get better  signal statistics from multiple captures.
Combine all these features into what you are doing - and this will be a complete marvel.

Thanks,
Title: ZERO NOISE technique
Post by: Guillermo Luijk on September 27, 2007, 09:08:44 AM
Quote
if you could also add a superresolution algorithm to ths program, this will be priceless.
There is a program PhotoAcute (photoacute.com) it works, but only on small images, it cannot be used for high end photography.

I started this post: http://luminous-landscape.com/forum/index....showtopic=19860 (http://luminous-landscape.com/forum/index.php?showtopic=19860)
(Multishot superresolution software) as I am looking for a solution to digitize my 6x7 negatives using Mamiya ZD, yet at a higher resolution than the sensor can record. PhotoAcute can create higher resolution images due to sub-pixel misalignment of the originals, it also cleans noise as you get better  signal statistics from multiple captures.
Combine all these features into what you are doing - and this will be a complete marvel.

Yes, I saw with great interest the PhotoAcute website and was amazed by the superresolution feature. But believe me, what I do is really really SIMPLE, absolutely not much technical background needed.
Algorithms such as those from PhotoAcute are only at reach of real men, and I am not at all. lol
Title: ZERO NOISE technique
Post by: Quentin on September 27, 2007, 12:28:41 PM
Hi Guillermo,

Thanks and noted about the ZD support.

As to my shots, you are much too kind; I'm just a hack who will benefit enormously from your software  

Cheers

Quentin
Title: ZERO NOISE technique
Post by: Diapositivo on September 27, 2007, 02:01:17 PM
Quote
GLuijk,
In what way would you say your method is better than standard blending procedures as outlined in this Luminous Landscape tutorial?

http://www.luminous-landscape.com/tutorial...-blending.shtml (http://www.luminous-landscape.com/tutorials/digital-blending.shtml)
[a href=\"index.php?act=findpost&pid=124781\"][{POST_SNAPBACK}][/a]

The blending tecnique(s) described in the mentioned articles are some kind of substitute for "Curves" when the scenes has a contrast that streches beyond the dynamic range and curves don't work. The result is always to lighten up the shadows or dodging the highlight in order to recover detail and legibility where it would be lost.

GLuijk tecnique can be used to recover details in the higlights but can be used also with a totally different goal: the lowlights are not made brighter, but less noisy. The picture has the same exposure but looks as if was taken with an "ideal" camera, with almost no noise.

I find this is new, extremely interesting, and absolutely to be encouraged.

Also I find that if the tecnique works with scanned film, this would give film a renewed interest, because only if you shoot film the tecnique can be applied also to handheld shots, and to shots with flames, leaves moving under the effect of the wind, persons running... in the slide everything is still.

I find this extremely interesting

Fabrizio
Title: ZERO NOISE technique
Post by: Guillermo Luijk on September 27, 2007, 05:49:16 PM
Quote
GLuijk tecnique can be used to recover details in the higlights but can be used also with a totally different goal: the lowlights are not made brighter, but less noisy. The picture has the same exposure but looks as if was taken with an "ideal" camera, with almost no noise.

It's funny that absolutely ANY blending tool (PS HDR, Photomatix,...) has necessarily to do this at some initial stage: blend the images without altering its original parameters. Unluckily none of them stops there, and all seem to be wanting to fiddle with your image: tone mapping, brightness and contrast adjustments, strange exposure corrections,...

Thanks.
Title: ZERO NOISE technique
Post by: Diapositivo on September 27, 2007, 08:10:26 PM
I am new to this forum (and its interface) and when I wrote this comment to an insertion in the first page I did not notice that there where 7 more pages of comment. So I read them all now. Absolutely instructive.

I discovered a version of your program is already born, but only for RAW formats.

I would like to stress that the two exposures with different shutter time can be made only with tripod and in particular circumstances (still life, very broadly speaking).

But for those scanning film, this tecnique can be used always! This would make a program that would handle scanned TIFFs superarchgigauseful!

So may I timidly suggest that either yourself, or somebody with the algorithm, write an "action" for PS or a stand-alone program that do the same with two TIFFs, one normally exposed and the other overexposed.

With my scanner (Nikon LS 5000 ED) I tried to acquire 2 TIFFs: one at normal exposure, and one with +2 EV analogue gain (cannot go further than +2). I then used them with two of the tecniques in the abovementioned LL tutorial, they seem to me perfectly aligned and the result is extended DR in a very clean way (using the second of the three methods).

So, if the scanner is capable of producing 2 TIFFs which are perfectly aligned already with PS CS2 (and easily alignable with PS CS3 as far as I understand) and that can be used for HDR (good news) maybe also your noise reducing tecnique could be used with film scans and with enormous benefits (yes also scanners suffer from lowlights noise). I understand doing the thing in RAW is cleaner and gives better results, but I would give it a try.

(Now that I think about it, actually I can save scans in Nikon native RAW format but don't know what am I supposed to do with them and have always ignored the RAW. Maybe I can pass them to the RAW processing software you wrote your program for)

Cheers
Fabrizio
Title: ZERO NOISE technique
Post by: Guillermo Luijk on September 28, 2007, 03:31:43 PM
That's possible. Actually I start from RAW files because I want to start from linear TIFF images, and the only way I found to have linear TIFFs from the beginning (since 99.99999% of TIFF images in this world are gamma corrected), was to develop the linear RAWs myself from my code.

But the concept is general and can be applied to gamma corrected images. The main problem is not actually the gamma (undoing it is trivial Maths). The problem is that TIFF files are usually not just gamma corrected images. They have also been converted to some colour space (means matrix operations that modify all RGB data) and have been adjusted in contrast (means all levels have moved again), brightness and so forth.

No idea what kind of TIFF and parameters can be adjusted in a scanner (never used one), but we would need TIFFs with as few adjustments as possible (apart from gamma). BTW if gamma can be set to 1.0 in the scanner settings (I doubt it) it would be perfect.
Title: ZERO NOISE technique
Post by: MichaelEzra on September 28, 2007, 04:03:48 PM
GLuijk,

I have Nikon Collscan 8000 which can generate NEF raw files.
I you would like, I can provide samples at various exposure levels, let me know the specifics.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on September 28, 2007, 04:09:20 PM
Quote
GLuijk,

I have Nikon Collscan 8000 which can generate NEF raw files.
I you would like, I can provide samples at various exposure levels, let me know the specifics.
[a href=\"index.php?act=findpost&pid=142483\"][{POST_SNAPBACK}][/a]

there is actually no limitation, just try to set the same white balance in all the shots. sorry, in all the scans lol

how much can you increase the exposure level?
if you provide me with 3 NEF scans, the regular one with no blown pixels, and two additional at +3EV and +6EV, we can do a nice test.

Send them through yousendit to: gluijk(at)hotmail.com

PS: choose a difficult scene, high dynamic range for instance, with which you didn't feel happy doing just one scan (poor detail in the shadows, noise,...).
Title: ZERO NOISE technique
Post by: gingerbaker on October 02, 2007, 12:53:55 PM
I use an automated luminosity mask blending technique using PS2 which I think has a similar effect on noise.

I use it with several exposures, however, as I use it to create extended dynamic range images, rather than using it just to remove noise in shadow areas.

I'm not sure if it will work with only two exposures, however - Glijik's technique looks a lot more sophisticated behind the scenes.

I'll bet there are folks here who could improve this technique with their "Blend if..." expertise.  

Anyway, here it is for Photoshop:

How to do Automated Luminosity Masking


1a) Open up the two images to blend.  If you have a bunch of the same scene using a tripod, and want a blend using the whole dynamic range, it is better to make multiple blends, each of exposures *not too far apart from each other*

1b)Using  move tool, SHIFT-left click to drag darker image onto lighter image
1c) Minimize the 1st dark image

2) Important - - verify alignment by Layer window ( where you see the layers, layer masks, etc) options list - Use Difference mode.  Zoom in is best, so that you can move image by pixil at a time using arrow keys.  -> be sure to set Layers Mode back to normal when done!

3) ALT-left click on eye icon on background ( lower) layer.  The picture should become lighter.

4) CONTROL-SHIFT-ALT- ~ ( tilde key)   creates luminosity mask. Hit all four of these keys simultaneously.  You should now see “marching ants” delineating the highlights.

5) ALT-click missing eye icon (hit the space where it used to be) on the upper layer.  The picture should now turn very dark. i

6) Go to the main “LAYERS” menu at top of screen, , select “Add layer mask” and “reveal selection”.  (Boom!)

to improve:

7) ALT-click on layer mask icon ( on original layer, to the right.  This will be the upper layer of the two, and all the way tot he right)

8) Gaussian blur of about 3 pixils - apply. This should sharpen the pic.  To check, zoom in, click ( not alt-click) on the layer thumbnail, to the left of the layer mask thumbnail.

To improve more:

9) again, click  ( not alt-click), on the layer mask thumbnail to activate it. Open up the LEVELS box in the Adjustments section, and  adjust blend using “Levels” adjustments.  Basically slide the middle slider to the right to “blend” the relative contributions of the two pictures.
Title: ZERO NOISE technique
Post by: Natasa Stojsic on October 12, 2007, 10:06:11 AM
Hi Guillermo,

Any chance for your Software Release before Christmas?

[span style=\'font-size:11pt;line-height:100%\']Optimist [/span]
Title: ZERO NOISE technique
Post by: Guillermo Luijk on October 12, 2007, 10:31:19 AM
Quote
Hi Guillermo,

Any chance for your Software Release before Christmas?

[span style=\'font-size:11pt;line-height:100%\']Optimist [/span]
[a href=\"index.php?act=findpost&pid=145507\"][{POST_SNAPBACK}][/a]

I hope so! although I will be on vacation in Namibia from tomorrow for the next 3 weeks.

I was this morning shooting at a typical-for-tourists restaurant in Madrid downtown, those places plenty of disgusting bull heads hanging from the walls. And the routine worked perfect to recover all hair texture in the black bulls (there were two of them) which were full of noise in the least exposed shot, at the same time as light areas were not blown. Worked very well.
Title: ZERO NOISE technique
Post by: Natasa Stojsic on October 15, 2007, 10:10:37 AM
Quote
I hope so! although I will be on vacation in Namibia from tomorrow for the next 3 weeks.

I was this morning shooting at a typical-for-tourists restaurant in Madrid downtown, those places plenty of disgusting bull heads hanging from the walls. And the routine worked perfect to recover all hair texture in the black bulls (there were two of them) which were full of noise in the least exposed shot, at the same time as light areas were not blown. Worked very well.
[a href=\"index.php?act=findpost&pid=145513\"][{POST_SNAPBACK}][/a]


Glad to hear that, Thanks

[span style=\'font-size:11pt;line-height:100%\']Have a nice trip!!![/span]
Title: ZERO NOISE technique
Post by: user on November 06, 2007, 09:31:14 AM
please tell me the requirements for zero noise images
Title: ZERO NOISE technique
Post by: DarkPenguin on November 06, 2007, 09:12:29 PM
Quote
please tell me the requirements for zero noise images
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=150894\")

Read this thread ...

[a href=\"http://luminous-landscape.com/forum/index.php?showtopic=17775]http://luminous-landscape.com/forum/index....showtopic=17775[/url]
Title: ZERO NOISE technique
Post by: Ray on November 06, 2007, 10:06:04 PM
Quote
The blending tecnique(s) described in the mentioned articles are some kind of substitute for "Curves" when the scenes has a contrast that streches beyond the dynamic range and curves don't work. The result is always to lighten up the shadows or dodging the highlight in order to recover detail and legibility where it would be lost.

GLuijk tecnique can be used to recover details in the higlights but can be used also with a totally different goal: the lowlights are not made brighter, but less noisy. The picture has the same exposure but looks as if was taken with an "ideal" camera, with almost no noise.


[a href=\"index.php?act=findpost&pid=142253\"][{POST_SNAPBACK}][/a]

I don't think this is quite true. Whatever method of image blending is used, the principle for getting less noise in the shadows is always to have an image that is correctly exposed for the shadows, which in a high contrast scene necessarily means an image with blown highlights.

Like-wise, in order to get detail in the highlights (with a contrasty scene) one needs an image correctly exposed for the highlights, which also necessarily means an image which is very noisy in the shadows. This applies to Gluijk's method also. There's no getting away from it.

When blending with the method described in the LL tutorial, one always has a degree of control over the individual layers after the blending procedure is completed, just as one has a choice as to how much EC to apply to each RAW image before converting. The result therefore is not to lighten the shadows, but to blend an image with noise-free shadows and blown highlights, with an image with detailed highlights and noisy shadows. How dark or light those shadows are in the final blend is entirely up to you. If you want them darker, then use the 'levels' control for that particular layer to make them darker. If you want them lighter just to see how much noise is there, you will find that there is very little noise, providing the overexposed shot was at least 3 stops overexposed.
Title: ZERO NOISE technique
Post by: user on November 07, 2007, 03:25:05 AM
Quote
Read this thread ...

http://luminous-landscape.com/forum/index....showtopic=17775 (http://luminous-landscape.com/forum/index.php?showtopic=17775)
[a href=\"index.php?act=findpost&pid=151017\"][{POST_SNAPBACK}][/a]

I don't quite understand:
do I need to take the same photo two times? with different camera settings each time? and then somehow merge them?

what about photos that we don't have the time or cannot take two times?

and why no camera manufacturer hasn't implement this technique to happen automaticaly?
Title: ZERO NOISE technique
Post by: jani on November 07, 2007, 04:46:33 AM
Quote
I don't quite understand:
do I need to take the same photo two times? with different camera settings each time? and then somehow merge them?
Yes.

Quote
what about photos that we don't have the time or cannot take two times?
Then you're s**t out of luck with those photos; you just have to make the best of the camera's limitations.

Quote
and why no camera manufacturer hasn't implement this technique to happen automaticaly?
At this point in time, it probably is too resource intensive to do in-camera. It may be possible some time in the future.
Title: ZERO NOISE technique
Post by: user on November 07, 2007, 05:09:45 AM
Quote
At this point in time, it probably is too resource intensive to do in-camera. It may be possible some time in the future.
[a href=\"index.php?act=findpost&pid=151053\"][{POST_SNAPBACK}][/a]

mm what if I set the camera to shoot automaticaly 2 times with the minimum time between shots?
Title: ZERO NOISE technique
Post by: Ray on November 07, 2007, 06:51:36 AM
Quote
mm what if I set the camera to shoot automaticaly 2 times with the minimum time between shots?
[a href=\"index.php?act=findpost&pid=151058\"][{POST_SNAPBACK}][/a]

Buy yourself Adobe CS3 or better still CS3 Extended. These latest versions of Photoshop have excellent auto-alignment features. Ideally you should use a tripod, but I've found this is not necessary if you can hold the camera reasonably steady for a second or so.

Use the 3 auto-bracketed exposures with a +/- 2 stop interval, which most cameras support, and merge to HDR in Photoshop.
Title: ZERO NOISE technique
Post by: EricV on November 07, 2007, 01:20:15 PM
Quote
But for those scanning film, this tecnique can be used always! This would make a program that would handle scanned TIFFs superarchgigauseful![{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=142330\")
SilverFast scanning software already does this.
[a href=\"http://www.silverfast.com/highlights/multi-exposure/en.html]http://www.silverfast.com/highlights/multi-exposure/en.html[/url]
Title: ZERO NOISE technique
Post by: Guillermo Luijk on November 07, 2007, 03:34:14 PM
Quote
I don't think this is quite true. Whatever method of image blending is used, the principle for getting less noise in the shadows is always to have an image that is correctly exposed for the shadows, which in a high contrast scene necessarily means an image with blown highlights.

Like-wise, in order to get detail in the highlights (with a contrasty scene) one needs an image correctly exposed for the highlights, which also necessarily means an image which is very noisy in the shadows. This applies to Gluijk's method also. There's no getting away from it.

When blending with the method described in the LL tutorial, one always has a degree of control over the individual layers after the blending procedure is completed, just as one has a choice as to how much EC to apply to each RAW image before converting. The result therefore is not to lighten the shadows, but to blend an image with noise-free shadows and blown highlights, with an image with detailed highlights and noisy shadows. How dark or light those shadows are in the final blend is entirely up to you. If you want them darker, then use the 'levels' control for that particular layer to make them darker. If you want them lighter just to see how much noise is there, you will find that there is very little noise, providing the overexposed shot was at least 3 stops overexposed.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=151026\")

Well Ray, I have to say what Diapositivo said is right: my routine just generates an image free of noise in the shadows, but with the same exposure, bright, contrast,... and everything as the least exposed shot of the set used. Therefore it is very dark and is the user's choice to choose the best way to lift the shadows where and as much as he wants. I wanted a routine that does not modify the original image's parameters in any way.

On this link you can try this with a real image produced by my program (I only converted it to sRGB from linear and re-scaled it down to a reasonable size, but didn't modify any level or characteristic of it): [a href=\"http://www.guillermoluijk.com/download/11m.tif]FREE OF NOISE HDR IMAGE[/url] (13MB).

You will see it is very dark (it has to be, otherwhise highlights would blow as you stated) but the shadows have such a high tonal richness (for being the result of a severe exposure correction down) that you can easily lift them with a curve and will find no posterization or noise problems. Try it!

(http://img111.imageshack.us/img111/6033/11mbf9.jpg)

by applying severe lifting curves...

(http://img232.imageshack.us/img232/1309/11m2oi6.jpg)

The image was produced from 3 shots, 3 f-stops apart, in a scene of 13 f-stops of real dynamic range, totally out of reach for any of our cameras in one single shot (Canons and Nikons reach about 8 f-stops):

(http://www.guillermoluijk.com/tutorial/histogrammar/histolinlog.gif)



Quote
and why no camera manufacturer hasn't implement this technique to happen automaticaly?
As far as I know, only one vendor has done this: Fuji on his Fujifilm Super CCD SR sensor, which performs real in-camera HDR. It consists of two separate sensors in one, sharing the same surface. They capture the scene with a relative exposure of 3.6EV (I have calculated this figure which after a good number of tests seems to be a constant parameter), and thanks to this the Fuji S3 Pro and S5 Pro can enhance their DR up to 11 f-stops, about 3 complete f-stops more than any Canon or Nikon around at the moment. The two images are independent from each other, and can be extracted and developed separately from the RAW file.

This article is in Spanish but I think looking at the pictures you can find out how it works: FUJI SUPER CCD. IN-CAMERA HDR (http://www.guillermoluijk.com/article/superccd/index.htm)

This is a cut of the 2 images contained in a RAW file from the Fuji: the S sensor has the task to get detail in the shadows (having the highlights blown), while the 3.6EV less exposed R sensor takes care of the highlights (having too much noise in the shadows):

(http://www.guillermoluijk.com/article/superccd/comp.jpg)

By properly blending both images (I did it with my own routine) we get both noise-free shadows and non-blown highlights:

(http://www.guillermoluijk.com/article/superccd/claustro.jpg)
Title: ZERO NOISE technique
Post by: sniper on November 07, 2007, 04:58:29 PM
When will your software be available?   Wayne
Title: ZERO NOISE technique
Post by: docmaas on November 07, 2007, 05:09:55 PM
Welcome back.  I discovered this thread just after you left.  I hope when you write your program you will include the sigma x3f raws in it.  

I am sure there are many of us hanging on to this thread waiting for further news.

Best

Mike
Title: ZERO NOISE technique
Post by: Guillermo Luijk on November 07, 2007, 05:31:25 PM
Quote
Welcome back.  I discovered this thread just after you left.  I hope when you write your program you will include the sigma x3f raws in it. 

I am sure there are many of us hanging on to this thread waiting for further news.

Best

Mike
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=151159\")

Thank you. Actually since I am not developing the files myself but using [a href=\"http://www.guillermoluijk.com/tutorial/dcraw/index_en.htm]David Coffin's DCRAW[/url], the formats supported will be those supported by DCRAW, which is a wide list (http://cybercom.net/~dcoffin/dcraw/index.html#cameras) (at present I think is the only RAW developer which can deal with Nikon D300 RAW files hehe).

Is your camera one of these?
- Sigma SD9
- Sigma SD10
- Sigma SD14

They are supported.

I would like to write some code this weekend.
Title: ZERO NOISE technique
Post by: docmaas on November 07, 2007, 08:10:46 PM
I have all three but the sd10 is broken.  Great to hear.  

thanks,

Mike

Quote
Thank you. Actually since I am not developing the files myself but using David Coffin's DCRAW (http://www.guillermoluijk.com/tutorial/dcraw/index_en.htm), the formats supported will be those supported by DCRAW, which is a wide list (http://cybercom.net/~dcoffin/dcraw/index.html#cameras) (at present I think is the only RAW developer which can deal with Nikon D300 RAW files hehe).

Is your camera one of these?
- Sigma SD9
- Sigma SD10
- Sigma SD14

They are supported.

I would like to write some code this weekend.
[a href=\"index.php?act=findpost&pid=151164\"][{POST_SNAPBACK}][/a]
Title: ZERO NOISE technique
Post by: Ray on November 07, 2007, 10:19:26 PM
Quote
Well Ray, I have to say what Diapositivo said is right: my routine just generates an image free of noise in the shadows, but with the same exposure, bright, contrast,... and everything as the least exposed shot of the set used. Therefore it is very dark and is the user's choice to choose the best way to lift the shadows where and as much as he wants. I wanted a routine that does not modify the original image's parameters in any way.

[a href=\"index.php?act=findpost&pid=151132\"][{POST_SNAPBACK}][/a]

Guillermo,
I can see that your method could have some advantages with regard to ease of processing. If one has difficulty in getting the desired result, as many people seem to, often with merged to HDR images, it's not clear whether the procedure itself makes it impossible to get the right result or whether the user is not skilled enough to get the desired result with that particular procedure.

The 'Layer Mask' method in the LL tutorial gives you a blended image with two layers, one representing the shadows and the other the highlights. One has to play around with these two layers, adjusting the levels, whatever, until the image looks right. Sometimes the image might never look right, possibly due to the fact that the initial exposures were too far apart, or due to one or both of the the RAW images requiring a different EC adjustment on conversion.

I'm all in favour of simplifying techniques for the user. I thought the shadow/highlight control first intoduced in PSCS was a really useful improvement to Photoshop, as is the new contrast/brightness tool in CS3 which protects the highlights.

In your example image of what looks like a deserted car park, the initial image is so dark, it would hardly matter if there were noise in the shadows. In lightening the image to demonstrate how noise-free the shadows are, you've lost detail in the highlights.

If you had used the 'layer mask' method in the LL tutorial, you would have been able to lighten that image by adjusting only the 'dark' layer without losing any highlight detail.  
Title: ZERO NOISE technique
Post by: Guillermo Luijk on November 08, 2007, 02:29:45 AM
Of course Ray, I just applied a global lifting curve to show that all the information is available and noise-free, both in the shadows and in the highlights. But for a proper edition is the user who has to play with the layer mask of the curves or any other tool available to get the desired 'manual tone mapping'. What I wanted to avoid is that a program (like Photomatix and etc...) decides for me where and how much the shadows are to be lifted obtaining unrealistic results.

So the result provided is simply what you would get with a noise-free camera that allows to capture the whole dynamic range in the shadows when setting the exposure to preserve the highlights of the scene, and it is you who decide now your preferred edition method.

A more adequate edition of that image obtaining the perceived atmosphere of the place could be (I think I only used a curve without layer mask but taking care of preserving the light hole):

(http://www.guillermoluijk.com/tutorial/histogrammar/resultgamma.jpg)

BTW that strange place is not a car park hehe, it is a very weird commemorial that was built for the 200 victims killed in Madrid by Al Qaeda. The light coming from the roof is natural light taken from outside and the place is deliberately poorly lighted resulting in a high dynamic range scene to our eyes.
Title: ZERO NOISE technique
Post by: MichaelEzra on November 08, 2007, 09:14:27 AM
Guillermo,

This is a wonderful method of obtaining HDR image. The tonemapping operation to get the LDR image is the next step:)! One could also use a free Picturenaut from hdrlabs.com

I will try to send you the NEF files from the Nikon Coolscan 8000 scanner tonight.
Title: ZERO NOISE technique
Post by: Ray on November 08, 2007, 01:47:23 PM
Quote
So the result provided is simply what you would get with a noise-free camera that allows to capture the whole dynamic range in the shadows when setting the exposure to preserve the highlights of the scene, and it is you who decide now your preferred edition method.
[a href=\"index.php?act=findpost&pid=151244\"][{POST_SNAPBACK}][/a]

Guillermo,
The 'Layer/mask' method outlined in the LL tutorial does have its difficulties, namely halos that sometimes occur at abrupt transitions between dark and light areas. I was initially interested in your method because it seemed to solve this problem.

However, HDR in CS3 seems to work just fine with only 2 images and with no halo problems.

The fact is, in this situation of blending 2 images, one cannot get less noise than the least noisy of the two images, which is the overexposed image or the image correctly exposed for the shadows.

It occurred to me that the relatively clean shadows in the overexposed image might get contaminated with noise from the underexposed image during the blending process to HDR. If this were the case, then your method would have a clear advantage because, as you've explained it, the pixel values are unchanged. Your blended image consists of either pixels from one image or the other, whereas the other blending methods probably create new values that don't exist in either image prior to blending.

I think there's probably no better test of blending methods than to shoot a scene from inside a room of the view through a window. The contrast is extremely high and the transition from light to shade around the window frame is very sharp.

So to settle this matter in my own mind, ie. whether the blended image is more noisy in the shadows than the unblended overexposed image, I took a few shots of the window in my rather squalid apartment which I'm renting for $10 a day on a monthly basis with unlimited broadband included. (Saving up for a 5D MkII, see   ).

[attachment=3753:attachment]  [attachment=3754:attachment]  [attachment=3755:attachment]

[attachment=3756:attachment]  [attachment=3757:attachment]

The final image compares 100% crops of the shadows in the overexposed image prior to merging to HDR, with the same area after merging to HDR and lightening.

To my mind, noise levels are about the same in each crop.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on November 08, 2007, 03:11:57 PM
mmm this is very interesting Ray, I always thought PS HDR was progressive in the entire image area, but your test shows that at least in some areas it takes just the information from the overexposed shot (which is the optimum). In fact I saw a video of PS HDR merging of different shots on a street scene with walking people, and they all appeared as ghosts (semi transparent people), which meant progressive blending.

I only have CS2 and trying PS HDR with it I got this non-optimum results in some areas (see background wall below), so as strange artifacts in the highlights due to interference of the overexposed shot (see lamp below).
Maybe CS3 has fixed these problems, could you please try this image with your CS3 to find out? these are the RAW files:

SUB.CR2 (http://www.guillermoluijk.com/download/sub.cr2)
SOBRE.CR2 (http://www.guillermoluijk.com/download/sobre.cr2)

(http://img125.imageshack.us/img125/4235/sample1us7.jpg)
(you can see a small slightly noisy area bottom left in the ZERO NOISE image, where the switch took place)

(http://img67.imageshack.us/img67/8069/sample2ju4.jpg)

Entire image:
(http://www.guillermoluijk.com/article/nonoise/resultado.jpg)

Regards

PS: BTW I always feel a bit embarrashed for showing such large pictures, but don't know how to set the 'click to enlarge' thumbnails from them. How should I do it?
Title: ZERO NOISE technique
Post by: Quentin on November 08, 2007, 04:09:44 PM
I hope Michael might review the software here on LL when it is ready.  In any event, my credit card stands ready to pay a fair price when its released.

Quentin
Title: ZERO NOISE technique
Post by: jule on November 08, 2007, 09:00:22 PM
Quote
Guillermo,


So to settle this matter in my own mind, ie. whether the blended image is more noisy in the shadows than the unblended overexposed image, I took a few shots of the window in my rather squalid apartment which I'm renting for $10 a day on a monthly basis with unlimited broadband included. (Saving up for a 5D MkII, see   ).

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I see you have air-con Ray...hope it works!

Julie
Title: ZERO NOISE technique
Post by: Ray on November 09, 2007, 12:47:59 AM
Quote
I see you have air-con Ray...hope it works!

Julie
[a href=\"index.php?act=findpost&pid=151421\"][{POST_SNAPBACK}][/a]

Julie,
The air-con works just fine. It's quite new but I don't need it just at the moment. It's quite cool in Chiang Mai at the monent.

Broadband in Australia seems to start off at A$29.95 per month for a very limited download of 200MB. Thereafter, the speed either drops down to dial-up 56kbps or one pays through the nose for additional megabytes. Also one usually has to sign a year's contract, which means it's going to cost more to take up the inevitable better offer that comes along in 3 months or 6 month's time.

It's no wonder John Howard is going to lose the next election. This government has been very slack in encouraging the development of broadband.

By contrast, unlimited high speed broadband in this hotel/apartment complex I'm staying at, in a relatively underdeveloped country, costs just A$27 per month for a minimum of 1 month. The room, about 40 sq m, is costing A$7.20 a day, plus broadband of 89 cents a day plus a small amount for electricity and water makes a total of around A$10 a day.
Title: ZERO NOISE technique
Post by: Ray on November 09, 2007, 01:48:49 AM
Quote
PS: BTW I always feel a bit embarrashed for showing such large pictures, but don't know how to set the 'click to enlarge' thumbnails from them. How should I do it?
[a href=\"index.php?act=findpost&pid=151364\"][{POST_SNAPBACK}][/a]

Guillermo,
It seems to be automatic when you download images from your computer's hard drive, rather than a website, using the 'Browse and Add Attachment' facility at the bottom of the 'reply' page.

But your method is better because the full size images are instantly viewable.

I've downloaded your 2 RAW images at lightning speed and tried a few blending techniques. In the process I managed to redecorate your apartment. Hope you like the result   . (Sorry about the spill on the floor and sofa, but we artistic types are a bit sloppy. We need someone to clean up, after).

[attachment=3765:attachment]

Could it be you have some colorful, fluorescent undercoating on your walls which  only CS3 can pick up?  

Seriously, this result only occurs when I convert the images before merging to HDR. Merging the RAw images produces a fairly normal result but still not satisfactory. These exposures are about 4 stops apart. I can only assume that the 'merge to HDR' process needs an intermediate exposure to get the tonalities right. So your method, at least with these two examples, would appear to be a big improvement on PS's HDR.

But I was curious as to how the layer/mask method described in the LL tutorial would handle these 2 images.

Here are the results. First the two converted images prior to blending. The dark image has been lightened by +1 EC and the light image has been darkened by -1 EC during conversion.

[attachment=3766:attachment]  [attachment=3767:attachment]

When applying the gaussian blur of the B&W mask I used a radius setting of 100 pixels. LL recommends 40 pixels, but this is variable according to circumstances. The following image shows the resulting blend without further levels adjustment of the two layers.

[attachment=3768:attachment]

The balance of this image seems about right in accordance with what the eye would see but probably still a little too dark in the deepest shadows, if you want to be literal.

I tried to match your very dark image, which is not what the eye would see, and came up with the following, by adjusting levels and contrast in the individual layers.

[attachment=3769:attachment]

Now for some noise-free 100% crops.

[attachment=3770:attachment]  [attachment=3771:attachment]  [attachment=3772:attachment]

I should mention that none of these images have been sharpened, which is one reason for their looking so noise-free. I'll also make a general comment that your images with your blending method seem slightly more even in the tonality. On the other hand, I don't know how the original scene really appeared to the eye.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on November 09, 2007, 06:06:29 AM
A lot of information in a single post, step by step:

1. I am a bit confused about those green colours PS CS3 HDR provided you in my sitting room, is that the only result than can be achieved? I merged the images in CS2 HDR and found non-optimum results and artifacts, but do you  mean CS3 HDR has got worse?  

2. I must admit I have not read LL method, but looking at your explanations I guess it consists of merging 2 versions of the same image with some difference in exposure, making use of a gaussian blur to make the blending progressive. Right?
Your result is great and natural, but I don't agree with this step: "The dark image has been lightened by +1 EC" since it means you are blowing 1 complete f-stop of information in the highlights.
However it will surely work also by leaving the dark image as is (so no loss of information), and applying a -2EV correction to the light image and then the LL method. Bright could be then controlled using a curve which preserves detail in the highlight while exposure correction doesn't.

3. Regarding the final crops, I wonder how the left area of the black cushion results in the LL method. The right side you showed seems to show a bit more noise (specially colour noise) than with my method (which would mean LL method took some info from the dark image even for the black cushion), but I wonder if you can show us the left side.

This is what I get in the right side of the cushion:
(http://img155.imageshack.us/img155/4529/rightnt0.jpg)

And this was the left side:
(http://www.guillermoluijk.com/article/nonoise/almohada.jpg)

PS: BTW I see you reescaled a bit down the image. For noise comparisions, if the image has necessarily to be reescaled it is VERY IMPORTANT to perform a nearest neighbout reescaling (in the Spanish version of PS it is called 'By Aproximation', and is the first option of PS reescaling methods, following next Bilinear and Bicubic).
Nearest neighbour reescaling just selects some unmodified pixels from the original image, therefore it preserves intact the signal to noise ratio as can be seen on a 100% crop, while any interpolation method (bicubic, bilinear,...) reduces noise thanks to pixel averaging.
Also integer 50%, 33.3%, 25%, 20%,... reescalings are recommended when using nearest neighbour to avoid aliasing artifacts.

Regards
Title: ZERO NOISE technique
Post by: Ray on November 09, 2007, 11:19:14 PM
Quote
1. I am a bit confused about those green colours PS CS3 HDR provided you in my sitting room, is that the only result than can be achieved? I merged the images in CS2 HDR and found non-optimum results and artifacts, but do you  mean CS3 HDR has got worse? 

Guillermo,
When using TIFFs for merge to HDR, a warning message appears to the effect that it's better to use RAW images. The conversions I used for HDR were the same as I used for the LL layer/mask technique. Obviously Photoshop's HDR program didn't like my settings   .

I tried again using the unconverted RAW images as advised, but there was still a hint of that discoloration. I've got no idea why. When I reconverted the RAW images with EC at zero and all the other settings at zero, the result was much improved as you can see in the comparison crops below.

This seems very strange to me. A warning message advising one to use RAW images, but a clearly better result when using TIFFs.

[attachment=3781:attachment]

Below is the full image after merging to HDR using TIFF conversions, followed by the lightened version using the shadows/highlight tool and a crop of the dark cushion lightened further. I'm not sure how these images will appear on a calibrated desktop monitor. I'm using a laptop which has been only roughly calibrated with Adobe Gamma.

[attachment=3782:attachment]  [attachment=3783:attachment]  [attachment=3784:attachment]

Quote
2. I must admit I have not read LL method, but looking at your explanations I guess it consists of merging 2 versions of the same image with some difference in exposure, making use of a gaussian blur to make the blending progressive. Right?
Your result is great and natural, but I don't agree with this step: "The dark image has been lightened by +1 EC" since it means you are blowing 1 complete f-stop of information in the highlights.
However it will surely work also by leaving the dark image as is (so no loss of information), and applying a -2EV correction to the light image and then the LL method. Bright could be then controlled using a curve which preserves detail in the highlight while exposure correction doesn't.

I'm not sure what's going on here under the hood. As I mentioned, this layer/mask technique tends to produce halos. To avoid getting halos, or to reduce the severity of the halos, it seems to be necessary to make EC adjustments at the conversion stage to minimise the tonal differences between the light image and the dark image, hence the light image -1 EC and the dark image +1 EC. I did not get the impression I was blowing highlights by using +1 EC with the dark image, perhaps because I also used the 'recover highlights' slider in ACR. Essentially the darker image has large specral highlights which always remain blown whatever the setting (ie. the inside of the lamp).

Below is the initial blended image from the layer/mask procedure using the same TIFFs I used for the above 'merge to HDR', ie. conversions with zero settings.

[attachment=3785:attachment]

It's difficult to now get rid of these halos with further adjustment. It's better to avoid them at the start. This is why I am interested in your method. However, HDR is producing a good result, no?

Quote
PS: BTW I see you reescaled a bit down the image. For noise comparisions, if the image has necessarily to be reescaled it is VERY IMPORTANT to perform a nearest neighbout reescaling (in the Spanish version of PS it is called 'By Aproximation', and is the first option of PS reescaling methods, following next Bilinear and Bicubic).
Nearest neighbour reescaling just selects some unmodified pixels from the original image, therefore it preserves intact the signal to noise ratio as can be seen on a 100% crop, while any interpolation method (bicubic, bilinear,...) reduces noise thanks to pixel averaging.
Also integer 50%, 33.3%, 25%, 20%,... reescalings are recommended when using nearest neighbour to avoid aliasing artifacts.

I didn't realise that. All the downsized full images have been rescaled using bucubic. The small 100% crops have not been rescaled but I did make changes from 240ppi to 72ppi whilst maintaining the same file size, ie. increasing the dimensions so the file size remains the same. Is that still rescaling?
Title: ZERO NOISE technique
Post by: Ray on November 10, 2007, 02:06:46 AM
Guillermo,
I've tried various conversion settings to try and find out what it is that HDR does not like in some of my converted tiff images. It appears to be the contrast of the dark image. It's not sufficient to have the contrast setting at zero in ACR. It must be at minus 50 to avoid that discoloration. However, it doesn't seem to make much difference if the contrast of the light image is set at zero or -50.

Nevertheless, the fact remains that I'm able to get a better result by making my own conversions instead of letting the HDR program do them.
Title: ZERO NOISE technique
Post by: simonkit on November 24, 2007, 07:18:27 PM
Some fascinating stuff on here - thanks all for the excellent info I'll certainly be giving the suggestions a try

 simon
Title: ZERO NOISE technique
Post by: wolfy on November 25, 2007, 01:48:42 PM
Quote
Jan, just because my post followed yours (I didn't quote yours either) doesn't mean my remarks were addressed solely to you: they were addressed to all those who when offered something for free were ungrateful and wanted more.
Peter
[a href=\"index.php?act=findpost&pid=139871\"][{POST_SNAPBACK}][/a]


Great thread and probably great product,...one which this Mac user will appreciate and pay for, if/when available. And would use via :"Virtual PC"-like application if available and effective.

Some support for Jani's comments:

Someone offers free shoes, ..mentioning a certain size. You ask if YOUR (different) size is available.

How is this indicative of un-gratefulness. It is a straightforward and reasonable QUESTION, no?

Why characterize the asking negatively? It only lends credence to the anti-Mac-user hostility mentioned by Jani.

BTW, Mac-only users (as opposed to users of both, such as yourself), are by definition excluded form the group which was  been "offered" something. The question was intended to find-out whether they would be included at some future time.

I have not seen anything posted in this thread indicating any non-appreciation of the OP's work, ...at most some respectful and reasonable questioning.

"Eye of the beholder", etc.  
Title: ZERO NOISE technique
Post by: Guillermo Luijk on March 24, 2008, 11:40:04 PM
Beta v0.9 version of Zero Noise, the program to automate this technique.

Hi all it's said it's better late than never. I took some time these days to finally develop the first beta version of the blending program to minimise noise and expand DR. There are still some things to improve and add, but at the moment its fully functional and performs nicely in the tests.

I will offer it for download very soon from my site with a tutorial on how to make use of it.

Meanwhile have a look at this micro-tutorial with an example. Sorry it's in Spanish (by now) but you can follow the images to find out.


Micro tutorial:

1. OPEN RAW FILES Se indica con la opción '...' el directorio donde están los RAW a fusionar.

Con elegir uno basta, el programa leerá los demás mostrando la imagen seleccionada y la lista total de RAWs (lo he autolimitado a 10 RAWs, pero usar más de 4 deja de tener sentido en cualquier aplicación. Con 3 haciendo bracketing 0,+2,+4 como en este ejemplo los resultados son buenísimos):

(http://img245.imageshack.us/img245/6692/dibuzt9.jpg)


2. WHITE BALANCE Se ajusta el balance de blancos. Como aún no está la opción de temperatura/matiz, y los multiplicadores lineales de DCRAW pueden ser poco intuitivos para el prueba/error, he introducido la posibilidad de seleccionar un parque rectangular o circular sobre la imagen que será balanceado en blancos. Este parche lo dibuja el usuario con tan solo clickear sobre la imagen:

(http://www.guillermoluijk.com/tutorial/zeronoise/gui2.jpg)

si se prefiere un parche circular porque la zona de interés para balancear se parece más basta pulsar el botón que indica un cuadrado:

(http://www.guillermoluijk.com/tutorial/zeronoise/gui3.jpg)


De las 2 posibilidades me quedo con la primera por resultar más natural:

(http://www.guillermoluijk.com/tutorial/zeronoise/compwb.jpg)


3. RAW DEVELOPMENT Una vez tenemos el balance de blancos deseado, no hay más que pulsar 'Develop' y el programa invocará a DCRAW para que revele los RAW. Para ver el progreso de DCRAW es bueno desactivar el checkbox llamado 'Hide MS-DOS' que hay en la parte de abajo:

(http://www.guillermoluijk.com/tutorial/zeronoise/dcraw.jpg)


4. BLENDING El paso anterior ha generado un archivo .tiff por cada RAW suministrado. Ahora solo hay que pulsar la opción 'Blend' (mezcla) y el programa los fusionará en una imagen final con el ruido minimizado pues tomará cada píxel del RAW menos ruidoso. Mostrará al final del proceso las exposiciones relativas entre tomas; este paso es muy importante, el programa calcula numéricamente cuáles fueron, ignorando los EXIF que pueden ser totalmente engañosos (subiré un ejemplo donde se ve esto muy bien):

(http://www.guillermoluijk.com/tutorial/zeronoise/gui4.jpg)

En un bracketing -2,0,+2 podemos ver que la separación en EV entre la primera y segunda toma no fue de 2EV sino menos. Caso de haber usado 2EV en la mezcla se habrían notado las transiciones entre zonas.


5. MANUAL TONE MAPPING El resultado será un .tiff lineal que se podrá leer en PS con tan solo asignarle una versión lineal del espacio de color que se usó como salida. De este enlace (http://stats.sergiodelatorre.com/dlcount.php?id=_GUI_&url=http://www.guillermoluijk.com/download/perfiles.zip) se pueden descargar versiones lineales de sRGB y de Adobe RGB.

Una vez cargada y asignada al espacio de color, con tan solo convertir la imagen al espacio de color destino (que puede ser el mismo en que la generamos, solo que ya no será una versión lineal), ésta se deslinealizará y quedará lista para ser editada como cualquier imagen revelada normal.

Esta imagen final parecerá bastante subexpuesta y sin contraste. La imagen NO ESTÁ SUBEXPUESTA, Y NO TIENE BAJO EL CONTRASTE, los tiene tal cual salen del RAW sin procesar. Es solo que acostumbrados a que ACR y demás reveladores apliquen por su cuenta curvas y ajustes de brillo éstas parecerán sosas.

Basta dos curvas (una de levantamiento de sombras y otra de contraste) para tener una imagen final correcta de alto rango dinámico, con las altas luces preservadas y bajo ruido en las sombras, sin haber hecho ninguna reducción de ruido que nos pudiera hacer perder texturas:

(http://www.guillermoluijk.com/tutorial/zeronoise/resultado.jpg)


Comparando la toma menos expuesta del conjunto inicial (la única en que no aparecía quemado el exterior de la ventana) con la toma resultante:

(http://img245.imageshack.us/img245/9603/compki3.jpg)
Title: ZERO NOISE technique
Post by: docmaas on March 24, 2008, 11:51:57 PM
Great News.  Looking forward to the release.

Best,

Mike

Quote
Beta v0.9 version of Zero Noise, the program to automate this technique.

Hi all it's said it's better late than never. I took some time these days to finally develop the first beta version of the blending program to minimise noise and expand DR. There are still some things to improve and add, but at the moment its fully functional and performs nicely in the tests.

I will offer it for download very soon from my site with a tutorial on how to make use of it.

Meanwhile have a look at this micro-tutorial with an example. Sorry it's in Spanish (by now) but you can follow the images to find out.
Micro tutorial:

1. OPEN RAW FILES Se indica con la opción '...' el directorio donde están los RAW a fusionar.

Con elegir uno basta, el programa leerá los demás mostrando la imagen seleccionada y la lista total de RAWs (lo he autolimitado a 10 RAWs, pero usar más de 4 deja de tener sentido en cualquier aplicación. Con 3 haciendo bracketing 0,+2,+4 como en este ejemplo los resultados son buenísimos):

(http://img245.imageshack.us/img245/6692/dibuzt9.jpg)
2. WHITE BALANCE Se ajusta el balance de blancos. Como aún no está la opción de temperatura/matiz, y los multiplicadores lineales de DCRAW pueden ser poco intuitivos para el prueba/error, he introducido la posibilidad de seleccionar un parque rectangular o circular sobre la imagen que será balanceado en blancos. Este parche lo dibuja el usuario con tan solo clickear sobre la imagen:

(http://www.guillermoluijk.com/tutorial/zeronoise/gui2.jpg)

si se prefiere un parche circular porque la zona de interés para balancear se parece más basta pulsar el botón que indica un cuadrado:

(http://www.guillermoluijk.com/tutorial/zeronoise/gui3.jpg)
De las 2 posibilidades me quedo con la primera por resultar más natural:

(http://www.guillermoluijk.com/tutorial/zeronoise/compwb.jpg)
3. RAW DEVELOPMENT Una vez tenemos el balance de blancos deseado, no hay más que pulsar 'Develop' y el programa invocará a DCRAW para que revele los RAW. Para ver el progreso de DCRAW es bueno desactivar el checkbox llamado 'Hide MS-DOS' que hay en la parte de abajo:

(http://www.guillermoluijk.com/tutorial/zeronoise/dcraw.jpg)
4. BLENDING El paso anterior ha generado un archivo .tiff por cada RAW suministrado. Ahora solo hay que pulsar la opción 'Blend' (mezcla) y el programa los fusionará en una imagen final con el ruido minimizado pues tomará cada píxel del RAW menos ruidoso. Mostrará al final del proceso las exposiciones relativas entre tomas; este paso es muy importante, el programa calcula numéricamente cuáles fueron, ignorando los EXIF que pueden ser totalmente engañosos (subiré un ejemplo donde se ve esto muy bien):

(http://www.guillermoluijk.com/tutorial/zeronoise/gui4.jpg)

En un bracketing -2,0,+2 podemos ver que la separación en EV entre la primera y segunda toma no fue de 2EV sino menos. Caso de haber usado 2EV en la mezcla se habrían notado las transiciones entre zonas.
5. MANUAL TONE MAPPING El resultado será un .tiff lineal que se podrá leer en PS con tan solo asignarle una versión lineal del espacio de color que se usó como salida. De este enlace (http://stats.sergiodelatorre.com/dlcount.php?id=_GUI_&url=http://www.guillermoluijk.com/download/perfiles.zip) se pueden descargar versiones lineales de sRGB y de Adobe RGB.

Una vez cargada y asignada al espacio de color, con tan solo convertir la imagen al espacio de color destino (que puede ser el mismo en que la generamos, solo que ya no será una versión lineal), ésta se deslinealizará y quedará lista para ser editada como cualquier imagen revelada normal.

Esta imagen final parecerá bastante subexpuesta y sin contraste. La imagen NO ESTÁ SUBEXPUESTA, Y NO TIENE BAJO EL CONTRASTE, los tiene tal cual salen del RAW sin procesar. Es solo que acostumbrados a que ACR y demás reveladores apliquen por su cuenta curvas y ajustes de brillo éstas parecerán sosas.

Basta dos curvas (una de levantamiento de sombras y otra de contraste) para tener una imagen final correcta de alto rango dinámico, con las altas luces preservadas y bajo ruido en las sombras, sin haber hecho ninguna reducción de ruido que nos pudiera hacer perder texturas:

(http://www.guillermoluijk.com/tutorial/zeronoise/resultado.jpg)
Comparando la toma menos expuesta del conjunto inicial (la única en que no aparecía quemado el exterior de la ventana) con la toma resultante:

(http://img245.imageshack.us/img245/9603/compki3.jpg)
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Title: ZERO NOISE technique
Post by: bernie west on March 25, 2008, 05:46:58 AM
good work Guillermo.  Can't wait to try it.
Title: ZERO NOISE technique
Post by: Dansk on March 25, 2008, 09:29:07 AM
Pretty nifty
Title: ZERO NOISE technique
Post by: feppe on March 25, 2008, 03:07:57 PM
Can't wait to get my mittens on this! Might need to do some new low-light shooting just to test it when it comes out
Title: ZERO NOISE technique
Post by: jmboss on March 27, 2008, 03:57:16 PM
Guillermo,

I hope your new program will significantly eliminate the noise issues that I encounter with my Mamiya 645/Leaf Aptus 17 when shooting under almost the exact same type of lighting conditions as the interior shot shown in your example.

Since the Leaf Aptus 17 raw file format is on the supported DCraw list, I suppose this is a good sign.

Thank you for your ongoing dedication and hard work involved in the production of this latest beta of the Zero Noise application.

Best Regards,

Joe Bossuyt
Title: ZERO NOISE technique
Post by: Quentin on March 27, 2008, 07:37:33 PM
Great, I look forward to the beta.

Quentin
Title: ZERO NOISE technique
Post by: Guillermo Luijk on March 28, 2008, 12:20:37 AM
The beta has been ready for download for the last days, but I still didn't have time to translate the tutorial into English. Wether you understand Spanish or just want to have a look:

ZERO NOISE DOWNLOAD (http://www.guillermoluijk.com/software/zeronoise/index.htm) (click DESCARGAR)

ZERO NOISE  TUTORIAL (http://www.guillermoluijk.com/tutorial/zeronoise/index.htm)


Regards.
Title: ZERO NOISE technique
Post by: MichaelEzra on March 28, 2008, 09:18:00 AM
GLuijk,
the download page has a link to histogrammar instead of zeronoisev0.9.zip
Title: ZERO NOISE technique
Post by: Guillermo Luijk on March 28, 2008, 10:07:25 AM
Quote
GLuijk,
the download page has a link to histogrammar instead of zeronoisev0.9.zip
[a href=\"index.php?act=findpost&pid=184940\"][{POST_SNAPBACK}][/a]

Hey Michael don't scare me please!!! my PC at home broke yesterday and I cannot modify any web content by now hehe. Where did you click?

I just tried and works fine:

(http://img135.imageshack.us/img135/4066/downnh3.jpg)
Title: ZERO NOISE technique
Post by: MichaelEzra on March 28, 2008, 10:42:13 AM
Hi Guillermo,

on this page:
http://www.guillermoluijk.com/software/zeronoise/index.htm (http://www.guillermoluijk.com/software/zeronoise/index.htm)

in the upper left corner the link is to
http://www.guillermoluijk.com/download/histogrammarv1.1.zip (http://www.guillermoluijk.com/download/histogrammarv1.1.zip)
(As seen with IE7)

I downloaded the app by simply guessing the file name:)

Do you have plans to enable those apetizing sliders for Gamma, etc on the application?

_____________
Btw, out of this topic, I found that the best solution to backup and restore entire machine, including OS is Acronis True Image (raid array friendly), highly recommend it.
Title: ZERO NOISE technique
Post by: Pantoned on March 28, 2008, 11:30:33 AM
Congratulations for your work, have been waiting for it for a long time!!

Just wanted to point out that I needed to download the "dcraw compiled with Microsoft compiler update" to be able to open my 1ds mark III files in vista. The normal version was working fine with 400d files.

Thanks for everything and keep up with this project!

Arnau.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on March 28, 2008, 12:50:58 PM
Quote
Do you have plans to enable those apetizing sliders for Gamma, etc on the application?

Definitively, I have great expectations about the gamma slider since it will allow to capture scences of more than 16 f-stops (yes 16!) of real dynamic range. For a 16-bit linear enconding 16 is a physical limit, and practical limit could be 12. By using the gamma for not losing levels in the shadows we can go beyond that limit when blending overexposed images.

But I would like to have feedback from you all, show your tests here. Both if they were fine or went wrong. That would encourage me a lot to add the new options.

Thanks for the advide, I could recover the system by reinstalling XP from the F11 recovery option, but the HD is about to die, I will install a new one, probably two, next week.

PS: I already corrected the link.
Title: ZERO NOISE technique
Post by: canmiya on March 28, 2008, 01:18:57 PM
an interim translation....and yes it is rough...
http://translate.google.com/translate?u=ht...&hl=EN&ie=UTF-8 (http://translate.google.com/translate?u=http%3A%2F%2Fwww.guillermoluijk.com%2Ftutorial%2Fzeronoise%2Findex.htm&langpair=es%7Cen&hl=EN&ie=UTF-8)
Title: ZERO NOISE technique
Post by: Iliah on March 30, 2008, 09:36:15 AM
Dear Sir,

Congratulations on making yet another one useful program.

Naysayers will always try to tell you they do not need it, that's fine because others do need it.

Most of us who deals with implementing raw conversions will support your point that substitutions (as well as stacking, blending, stitching) are best performed over the raw data. Demosaicing and gamma-correction of noisy data amplifies noise and propagates it through the colour channels. It takes more shots and more effort to get similar results after demosaicing, not to mention artefacts resulting from any demosaicing and caused by noise in raw data.

IMHO your program can write back the same raw file, without demosaicing, allowing to use regular raw convertors over it.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on March 30, 2008, 01:37:10 PM
Quote
Dear Sir,

Congratulations on making yet another one useful program.

Naysayers will always try to tell you they do not need it, that's fine because others do need it.

Most of us who deals with implementing raw conversions will support your point that substitutions (as well as stacking, blending, stitching) are best performed over the raw data. Demosaicing and gamma-correction of noisy data amplifies noise and propagates it through the colour channels. It takes more shots and more effort to get similar results after demosaicing, not to mention artefacts resulting from any demosaicing and caused by noise in raw data.

IMHO your program can write back the same raw file, without demosaicing, allowing to use regular raw convertors over it.

I totally agree, in fact the original idea was to do it all over the undemosaiced RAW data with assistance from a C-coder who managed to reutilise DCRAW code to access the RAW undemosaiced data (in this thread we talked about that and Jonathan Wienke even pointed that a DNG output would be a very good approach). But this guy became too busy with other projects so I went on alone and chose a demosaiced approach.

You give me new ideas for improvement. I have no idea of the DNG format, is it easy to build a DNG file from scratch? I think RAW formats are indeed quite complicated.

Just curious, are you Iliah Borg?

Regards.
Title: ZERO NOISE technique
Post by: Iliah on March 30, 2008, 03:26:41 PM
Dear Sir,

Yes, I'm Iliah Borg

Raw formats are complicated, but for the case when you need just to replace original sensor data with manipulated it is not so difficult. Native raw converters like Nikon's (NX), Canon's etc. do not support DNG, hence staying with native raw may have sense. DNG implementation is not too difficult, http://www.adobe.com/support/downloads/dng/dng_sdk.html (http://www.adobe.com/support/downloads/dng/dng_sdk.html)
Title: ZERO NOISE technique
Post by: Guillermo Luijk on March 30, 2008, 04:19:14 PM
Quote
Dear Sir,

Yes, I'm Iliah Borg

Raw formats are complicated, but for the case when you need just to replace original sensor data with manipulated it is not so difficult. Native raw converters like Nikon's (NX), Canon's etc. do not support DNG, hence staying with native raw may have sense. DNG implementation is not too difficult, http://www.adobe.com/support/downloads/dng/dng_sdk.html (http://www.adobe.com/support/downloads/dng/dng_sdk.html)
[a href=\"index.php?act=findpost&pid=185475\"][{POST_SNAPBACK}][/a]


Iliah it's an honour to have such an expert like you commenting in this thread. I heard about you because I shared some interesting posts in the past with your daughter Julia in dpreview (about linear RAW development and later about your UniWB), she's a tremendously qualified person about all these matters and willing to share knowledge.

I will take into account a possible DNG-output version after I have done some other improvements I have in mind. Perhaps it's beyond my capabilities, but it's worth a try.

There is one thing however I want to try that I think would not be possible with a linear RAW-output approach: I plan to apply the gamma (2.2 or whatever) in floating point calculations right before the final 16-bit integer rounding for output. This can provide much more levels for the lowest f-stops and hence a higher tonal richness and DR expansion. I think 16 f-stops and even more can be reached with no problem with this scheme (the problem will be to find such a huge DR scene in real life hehe).

Regarding this I have a question for you if you don't mind: to apply the gamma to a calculated {R,G,B} linear pixel I plan to do (gamma=2.2 for simplicity, all normalised values):

1. Calculate Y = k1*R + k2*G + k3*B according to some luminance k1+k2+k3=1.0 weighted average model

2. To apply gamma to luminance: Y' = Y^(1/2.2) = (k1*R + k2*G + k3*B )^(1/2.2)=K*Y  so K?
K=Y'/Y=Y^(1/2.2-1)=(k1*R + k2*G + k3*B )^(1/2.2-1)

3. So finally perform:
R' = R * K
G' = G * K
B' = B * K


Do you think this simple approach is right? I am fairly sure I am preserving tone (ratio between R, G and B is kept). But can this way to apply the gamma have some undesired consequence or caution? maybe related to the colour profile used...


Best regards.
Title: ZERO NOISE technique
Post by: ejmartin on March 30, 2008, 04:25:09 PM
Quote
I totally agree, in fact the original idea was to do it all over the undemosaiced RAW data with assistance from a C-coder who managed to reutilise DCRAW code to access the RAW undemosaiced data (in this thread we talked about that and Jonathan Wienke even pointed that a DNG output would be a very good approach). But this guy became too busy with other projects so I went on alone and chose a demosaiced approach.

You give me new ideas for improvement. I have no idea of the DNG format, is it easy to build a DNG file from scratch? I think RAW formats are indeed quite complicated.

Just curious, are you Iliah Borg?

Regards.
[a href=\"index.php?act=findpost&pid=185450\"][{POST_SNAPBACK}][/a]


I'd love to have an application that would allow me to manipulate the raw data and stuff it back in the original raw file, I just don't have the coding background.  IMO it's an application that is sorely missing and much needed.  There are so many tweaks that are better done on raw data and are not implemented well or at all in raw converters; HDR is but one.  It would be so nice to be able to preprocess the raw data, and then have the ability to run the preprocessed raw file through one's favorite converter.  

If you are able to implement such a feature, that would be great.  The code must be there implicitly in dcraw -- it can output an undemosaiced .pgm from the original raw data, it should therefore be possible to take a .pgm file and insert the same data (post manipulation) back in the raw file (or rather a duplicate of it).
Title: ZERO NOISE technique
Post by: ejmartin on March 30, 2008, 04:29:44 PM
Quote
Regarding this I have a question for you if you don't mind: to apply the gamma to a calculated {R,G,B} linear pixel I plan to do (gamma=2.2 for simplicity, all normalised values):

1. Calculate Y = k1*R + k2*G + k3*B according to some luminance k1+k2+k3=1.0 weighted average model

2. To apply gamma to luminance: Y' = Y^(1/2.2) = (k1*R + k2*G + k3*B )^(1/2.2)=K*Y  so K?
K=Y'/Y=Y^(1/2.2-1)=(k1*R + k2*G + k3*B )^(1/2.2-1)

3. So finally perform:
R' = R * K
G' = G * K
B' = B * K
Do you think this simple approach is right? I am fairly sure I am preserving tone (ratio between R, G and B is kept). But can this way to apply the gamma have some undesired consequence or caution? maybe related to the colour profile used...
Best regards.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=185493\")


You can find the equations for converting among color spaces at

[a href=\"http://brucelindbloom.com/]http://brucelindbloom.com/[/url]

under the "Math" section.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on March 30, 2008, 04:39:22 PM
Quote
You can find the equations for converting among color spaces at

http://brucelindbloom.com/ (http://brucelindbloom.com/)

under the "Math" section.
[a href=\"index.php?act=findpost&pid=185496\"][{POST_SNAPBACK}][/a]

Then I should do:

sRGB(gamma=1.0) -> XYZ
XYZ -> sRGB(gamma=2.2) ?

but if I am not missing something, in the end this means:
R' = R^(1/2.2)
G' = G^(1/2.2)
B' = B^(1/2.2)

which does not preserve the ratio between the colours, so tones change, don't they?
Title: ZERO NOISE technique
Post by: Iliah on March 30, 2008, 07:10:13 PM
Dear Guillermo,

As far as my experience is, in floating point the precision of calculations is quite enough not to bother with gamma. In fact, any unnecessary calculations like gamma effect the resulting image in a negative way.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on March 30, 2008, 07:50:02 PM
Quote
Dear Guillermo,

As far as my experience is, in floating point the precision of calculations is quite enough not to bother with gamma. In fact, any unnecessary calculations like gamma effect the resulting image in a negative way.

Right, but I necessarily have to go to 16-bit integer TIFF in the end. What I want to do then is perform gamma before this final rounding so that the overexposed images will fill the levels at the low end of the histogram, and the gamma will prevent those levels from aggregation.
Title: ZERO NOISE technique
Post by: Iliah on March 30, 2008, 08:03:56 PM
Dear Guillermo,

Quote
Right, but I necessarily have to go to 16-bit integer TIFF in the end.

Photoshop works with RGB TIFFs in floating point quite nicely. Even better, you can use http://www.openexr.com/ (http://www.openexr.com/) as an output format. Native support on NVIDIA cards allows for much faster calculations over bitmaps. There is a Photoshop plugin that allows to open EXR files.
Title: ZERO NOISE technique
Post by: barryfitzgerald on March 30, 2008, 08:56:15 PM
Intersting thread, have to say though..noise that is grain like, is not really a problem to me. I fear the meltmaster plastic look too much I am afraid.
Title: ZERO NOISE technique
Post by: ejmartin on March 30, 2008, 09:12:42 PM
Quote
You can find the equations for converting among color spaces at

http://brucelindbloom.com/ (http://brucelindbloom.com/)

under the "Math" section.
[a href=\"index.php?act=findpost&pid=185496\"][{POST_SNAPBACK}][/a]

Note that there are matrices M for converting among color spaces, in particular for converting from XYZ to rgb.  Furthermore, it sounds like you want to do a manipulation of the luminosity data in Lab space; the transformation between Lab and XYZ is more complicated than a simple gamma transformation, as you can see from the formulae on the linked site.
Title: ZERO NOISE technique
Post by: Jonathan Wienke on March 30, 2008, 10:14:21 PM
Quote
I fear the meltmaster plastic look too much I am afraid.

The plastic look is the result of noise reduction eliminating detail along with noise. Improving the S/N ratio of the capture with actual image data instead of mathematical guesswork will not cause a loss of detail; you get more actual subject texture instead of noise.
Title: ZERO NOISE technique
Post by: dave unwin on March 30, 2008, 11:31:03 PM
Very interesting thread and i'm looking forward to the official release!

As a bit of an aside, i have been very pleased with the Timothy Ames Enfuse plugin for lightroom which can provide a similar noise reduction, although without the control that your program seems to offer.

cheers
Title: ZERO NOISE technique
Post by: Iliah on March 31, 2008, 09:46:13 AM
Quote
The plastic look is the result of noise reduction eliminating detail along with noise.

Not only, it is quite often the result of suboptimal colour transforms and reducing colour gamuts beyond reasonable. In some cases it is CFA properties too.
Title: ZERO NOISE technique
Post by: Iliah on March 31, 2008, 09:48:55 AM
Quote
Note that there are matrices M for converting among color spaces, in particular for converting from XYZ to rgb.  Furthermore, it sounds like you want to do a manipulation of the luminosity data in Lab space; the transformation between Lab and XYZ is more complicated than a simple gamma transformation, as you can see from the formulae on the linked site.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=185561\")

To convert to high gamma space on a PC one needs a destination space and [a href=\"http://www.argyllcms.com/]http://www.argyllcms.com/[/url]
Title: ZERO NOISE technique
Post by: Guillermo Luijk on March 31, 2008, 09:30:37 PM
One interesting issue that arised on a Spanish forum: a Canon 30D user experienced these artifacts when blending 4 RAW files with ZN: transitions in the blend switching areas are visible:

(http://img522.imageshack.us/img522/564/recortesincurvas1lc6.jpg)(http://img514.imageshack.us/img514/243/recortesincurvas2zk1.jpg)(http://img81.imageshack.us/img81/3314/recorteconcurvas2il9.jpg)


ZN calculated wrong relative exposures because DCRAW does not apply a correct saturation point for this camera (I found out is also wrong with 40Ds), so the RAW developments went wrong. DCRAW uses saturation 4095 on Canon 30D while it is 3398. We can see that in the pure RAW histogram of a saturated file:

(http://img389.imageshack.us/img389/5416/4hisza9.gif)


I have set an option on ZN to set the saturation point which makes use of the wonderful option -S in DCRAW, recently introduced by David Coffin. Now relative exposures are correctly calculated:

Calculating relative exposure...
1.tiff: 1 (+0 EV)
2.tiff: 4,17 (+2,06 EV)
3.tiff: 17,06 (+4,09 EV)
4.tiff: 69,78 (+6,12 EV)
DONE

So final image before tone mapping (same exposure as 1.tiff):

(http://img219.imageshack.us/img219/7336/result0nn1.jpg)


Simple 2-curve tone mapping:

(http://img389.imageshack.us/img389/1916/blend235813gp2.jpg)


The transitions are now perfect, impossible to distinguish exposure gap.
Sample of SNR improvement with respect to 0EV shot (the only one that preserved the window):

(http://img370.imageshack.us/img370/9493/resultfb5.jpg)

And we can see a respectable real 13 f-stops of DR were captured.

(http://img389.imageshack.us/img389/3544/blend235813hisvs3.gif)


CONCLUSION: saturation point of the camera is very important. For those experiencing this kind of problems (30D, 40D) I will implement a camera combo box in the next version of ZN with proper adjustments to fix this. Also the user will be allowed to manually enter the saturation point.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on March 31, 2008, 10:08:31 PM
A brief step by step screenshot taken from Dpreview (thanks to the signatory in the Kodak SLR forum):

(http://img403.imageshack.us/img403/9794/znscreengrabmt9.jpg)
Title: ZERO NOISE technique
Post by: BruceHouston on March 31, 2008, 10:29:50 PM
Thank you again, Guillermo!

I look forward to the camera combo box version as I have a 40D.

Best regards,
Bruce
Title: ZERO NOISE technique
Post by: Iliah on April 01, 2008, 12:21:34 AM
Each camera sample may have its own saturation point. More, they depend on ISO settings sometimes. It is better to test both floor and saturation points of any given camera then to rely on the constants hardwired into a programme.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on April 01, 2008, 04:15:47 AM
Quote
Each camera sample may have its own saturation point. More, they depend on ISO settings sometimes. It is better to test both floor and saturation points of any given camera then to rely on the constants hardwired into a programme.

I agree. The problem is that this is a bit advanced for regular users.
What do you think commercial RAW developers such as ACR or Lightroom do? have a huge table of saturation points for each camera/ISO pair, or just trend to clip highlights with a conservative low saturation point?
Title: ZERO NOISE technique
Post by: Iliah on April 01, 2008, 11:12:43 AM
Quote
I agree. The problem is that this is a bit advanced for regular users.
What do you think commercial RAW developers such as ACR or Lightroom do? have a huge table of saturation points for each camera/ISO pair, or just trend to clip highlights with a conservative low saturation point?
[a href=\"index.php?act=findpost&pid=186036\"][{POST_SNAPBACK}][/a]

Normally converters use both approaches, meaning a table of conservative values

Two shots at each ISO setting, one with a lens cap on, the other - fully blown in each channel allow to make a table. Interesting that points for both green channels are not always the same. Next, camera serial number and a table of floor and saturation points make a nice base for improvement of raw conversion.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on April 01, 2008, 12:23:59 PM
Quote
Two shots at each ISO setting, one with a lens cap on, the other - fully blown in each channel allow to make a table. Interesting that points for both green channels are not always the same. Next, camera serial number and a table of floor and saturation points make a nice base for improvement of raw conversion.

Yes the first thing I thought of when I discovered the saturation point was not always 2^N-1, was that a very accurate RAW development could 'recover' a good amount of information in those shots that were erroneously taken with too high exposure values. In that way, commercial developers would not always be optimum.

Regarding the black level, I thought all cameras had hidden pixels so it was best let the developer analyse them to find the more precise black point to be substracted. At least DCRAW always worked fine for me in calculating that figure that varies quite a lot depending on exposure conditions.
Some cameras (like Nikon) unfortunately substract that offset in-camera, right?

BTW a friend of mine who has a Fuji S3 Pro has reported several times magenta casts in the highlights when using ACR to develop Super CCD RAW files. Probably the reason is a bit too high saturation point in ACR for the R captors in that camera model.
Title: ZERO NOISE technique
Post by: Plekto on April 02, 2008, 08:54:29 PM
Quote
Yes the first thing I thought of when I discovered the saturation point was not always 2^N-1, was that a very accurate RAW development could 'recover' a good amount of information in those shots that were erroneously taken with too high exposure values. In that way, commercial developers would not always be optimum.

Regarding the black level, I thought all cameras had hidden pixels so it was best let the developer analyse them to find the more precise black point to be substracted. At least DCRAW always worked fine for me in calculating that figure that varies quite a lot depending on exposure conditions.
Some cameras (like Nikon) unfortunately substract that offset in-camera, right?

BTW a friend of mine who has a Fuji S3 Pro has reported several times magenta casts in the highlights when using ACR to develop Super CCD RAW files. Probably the reason is a bit too high saturation point in ACR for the R captors in that camera model.
[a href=\"index.php?act=findpost&pid=186137\"][{POST_SNAPBACK}][/a]

Wow.  Digital photos that look like old-school film.  I'm impressed at how the largest three problems - dynamic range,  noise, and fringing are gone with your software.  You do need a way to manually enter the saturation point of a camera, since I suspect that each camera is a tiny bit different as well due to manufacturing and optical changes.(perhaps slightly different with each lens, even, though I suspect it's a very small value)

Q: what camera was used?  It's impressive to say the least.

I love the idea of applying this to a scanner as well.

Q2:Could you possibly change it to have "slots" that you put the files into, and then you can select which one is what value? (so it knows what order to properly blend everything if you have lots of pictures)  That way you could have 3 or 4 or even 12 exposures to blend together.(why not, digital "film" is not a factor here - most cards will hold 10-12 raw pictures)

This has honestly made me reconsider whether I should be looking at digital or not.

P.S. could someone who has a film scanner show an example of this as well?  Preferably a Minolta Pro with MF slide film?(probably have to use Silverfast, right?)
Title: ZERO NOISE technique
Post by: Jonathan Wienke on April 03, 2008, 12:23:04 AM
Quote
Wow.  Digital photos that look like old-school film.  I'm impressed at how the largest three problems - dynamic range,  noise, and fringing are gone with your software.

Welcome to the real world, Neo. Digital has obviously come a long way since you used it last; for most subjects, blending images is not necessary to keep shadow noise acceptably low. The only time you really need it is for high-DR situations like backlit subjects, interiors with brightly-lit windows, etc.

Quote
Q2:Could you possibly change it to have "slots" that you put the files into, and then you can select which one is what value? (so it knows what order to properly blend everything if you have lots of pictures)  That way you could have 3 or 4 or even 12 exposures to blend together.(why not, digital "film" is not a factor here - most cards will hold 10-12 raw pictures)

There is no point in blending more than 3 images. 3 images 3 stops apart are very difficult to blend into a single natural-looking image. There's a limit to how much you can compress DR.  See the "do you hate HDR too" thread for examples and discussion of this. 2 images is more than adequate in the majority of cases, and the more images you have the greater problems you have with alignment. And add a zero or two to your estimate of card capacity; the larger cards available can hold hundreds of RAW frames, possibly over 1000.

Quote
P.S. could someone who has a film scanner show an example of this as well?  Preferably a Minolta Pro with MF slide film?(probably have to use Silverfast, right?)

Film does not lend itself to DR blending as well as digital. Film has a non-linear response curve, which makes calculating the correct blend values accurately much harder. And if the film isn't perfectly flat when exposed and scanned, aligning multiple frames to blend becomes problematic.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on April 03, 2008, 05:00:32 AM
Quote
You do need a way to manually enter the saturation point of a camera, since I suspect that each camera is a tiny bit different as well due to manufacturing and optical changes.(perhaps slightly different with each lens, even, though I suspect it's a very small value)
Lens does not affect camera's saturation point. I am planning to introduce a 'Calibrate' button, so just by providing ZN a saturated picture it would calculate the exact saturation point to optimise RAW dvelopment for each particular camera.

As far as I know, they don't seem to differ too much between units of the same model: I have tested saturated RAW files from two 40D's and both saturated exactly at the same level (13000 something).


Quote
Q: what camera was used?  It's impressive to say the least.
If you mean in the sitting room sample, my Canon 350D.


Quote
Q2:Could you possibly change it to have "slots" that you put the files into, and then you can select which one is what value? (so it knows what order to properly blend everything if you have lots of pictures)  That way you could have 3 or 4 or even 12 exposures to blend together.(why not, digital "film" is not a factor here - most cards will hold 10-12 raw pictures)
The present version of the program allows for up to 10 RAW files (autolimited, I thought more is simply stupid) and they don't need to be ordered. The program will order them by exposure level and calculate (not read the EXIF) the relative exposure between each pair of images. If the program allowed the user to enter the EV differences between the shots, the result would probably be wrong and transitions would become visible due to exposure differences.


Quote
This has honestly made me reconsider whether I should be looking at digital or not.
Digital cameras have become really nice devices Plekto. Their Aquiles heel today is DR and they are continuously improving. With this technique you can avoid the limitations in DR, but with the important limitation that it requires a tripod and a static scene.



Jonathan, I remember you would be interested in a blending with a 16-bit DNG output. Many people have shown a lot of interest for this option. To do that is no problem as long as we know how to build a DNG from scratch, so anyone who knows about the DNG format and would like to make a pure RAW blending tool, just contact me. I think it is not that difficult.

However, in such an approach, it would be a must to have the possibility for anti-ghosting and allow progressive blending in the border areas, since the result will be difficult to correct making use of the original RAW files. I want to try mi anti-ghosting and progressive blending ideas in the next weeks.
Title: ZERO NOISE technique
Post by: MichaelEzra on April 03, 2008, 10:39:26 AM
Hi Guillermo,

you could probably contact Ed Hamrick (hamrick.com) regarding DNG output. His VueScan software has that capability, as well as blending of 2 exposres from a scanner input, but not from individually shot raw files. There is probably room for cooperation;)

Best,
Title: ZERO NOISE technique
Post by: Jonathan Wienke on April 03, 2008, 10:49:20 AM
Quote
Jonathan, I remember you would be interested in a blending with a 16-bit DNG output. Many people have shown a lot of interest for this option. To do that is no problem as long as we know how to build a DNG from scratch, so anyone who knows about the DNG format and would like to make a pure RAW blending tool, just contact me. I think it is not that difficult.

The complete DNG format specification can be found at http://www.adobe.com/products/dng/pdfs/dng_spec.pdf (http://www.adobe.com/products/dng/pdfs/dng_spec.pdf). It doesn't look that hard to write a DNG file once you have created all of the 16-bit linear RGB image data. I look forward to a version of Zero Noise that outputs DNG files with great interest.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on April 03, 2008, 07:11:25 PM
Just a sample of why I consider important to calculate the relative exposures ourselves, from whithin the code. The sample image (dinning room) was obtained from a {-2,0,2} camera bracketing, so to adjust exposure of the 0 shot to the -2 we would correct exposure by -2EV.

However ZN calculated less exposure correction: -1,91 to be exact:

Calculating relative exposure...
3.tiff: 1 (+0 EV)
2.tiff: 3,77 (+1,91 EV)
1.tiff: 15,06 (+3,91 EV)
DONE

Let's find out the difference in the final result when applying a -1,91EV correction, and what would have happened if we decided to apply -2,00EV:

(http://www.guillermoluijk.com/tutorial/zeronoise/calculo.jpg)


The -2EV reveals the transition area (best seen in the bottom pictures that were processed with a curve to enhance contrast) while the -1,91EV correction yields a much better gradation.

To be honest, I didn't care too much on optimising this calculation; I think it can even be improved to focus on the relative exposure on those image areas where the transitions are to happen.


BR
Title: ZERO NOISE technique
Post by: Plekto on April 03, 2008, 08:20:42 PM
Quote
Welcome to the real world, Neo. Digital has obviously come a long way since you used it last;

2 images is more than adequate in the majority of cases, and the more images you have the greater problems you have with alignment. And add a zero or two to your estimate of card capacity; the larger cards available can hold hundreds of RAW frames, possibly over 1000.
Dang. I must have chosen the wrong color...    

Yes I know about the capacities, too.  But even if you had to hold a 100MB raw file from a digital back, you could fit a ton of them on a single card these days.  Of course, this all isn't cheap.

I want the multiple exposures as an option for scenery and the like.  Setting it on the camera and then messing with this free software... beautiful results when you want it to look like film. (I've even seen focus blending - which is also amazing)

Quote
Film does not lend itself to DR blending as well as digital. Film has a non-linear response curve, which makes calculating the correct blend values accurately much harder. And if the film isn't perfectly flat when exposed and scanned, aligning multiple frames to blend becomes problematic.

I figured as much for the film.  I'd obviously need software to automate the process so that I don't have to touch anything.  But it also seems to be possible, and a cheaper alternative than digital MF backs.


Quote
As far as I know, they don't seem to differ too much between units of the same model: I have tested saturated RAW files from two 40D's and both saturated exactly at the same level (13000 something).

Nice to know.

Quote
If you mean in the sitting room sample, my Canon 350D.
The present version of the program allows for up to 10 RAW files (autolimited, I thought more is simply stupid) and they don't need to be ordered. The program will order them by exposure level and calculate (not read the EXIF) the relative exposure between each pair of images. If the program allowed the user to enter the EV differences between the shots, the result would probably be wrong and transitions would become visible due to exposure differences.

Very slick.  Just drop in and it figures it out.  Very good.  Yeah, that is easier than my idea.  Pay no attention to my ramblings... these are not the droids you are looking for....



Quote
Digital cameras have become really nice devices Plekto. Their Aquiles heel today is DR and they are continuously improving. With this technique you can avoid the limitations in DR, but with the important limitation that it requires a tripod and a static scene.

This I can probably deal with as the shots that I care about are exactly that sort of thing.  Some house or car or sunset whatnot that looks dreadful because of the shadows and the wide swaths of nearly continuous tones - often with the sun bouncing off of something or in the distance.

It does look like 3-5 exposures are needed, though, for best results.  Adding that third midrange shot cleaned up the middle tones quite considerably.  If you notice, 95% of the pictures that we enlarge or want to be large enough where this matters tend to be static pictures.  

I'm now looking for a camera that can do quick bracketing like this - so I don't have to mess too much.  But few seem set up for this - either they are limited to single steps instead of +/-2 or they only go to +/- 2 maximum(too limited), or can only do three shots.

But I'll find something, I'm sure   Being able to have it fire off 5 shots under in a second would make it much easier as alignment wouldn't be an issue(ie - I wouldn't touch it at all to change settings).  Just press the remote shutter release button(this is a good use for them - who would have thought... )and presto - I can blend 2 or 3 or 5 as it requires.  Then dump it into Photoshop or whatnot to get it ready to print.


Oh - I did have one other suggestion - one that I think you could actually charge money for if you put it in the program(I'd pay money for this):

- Have an option to automate the process.  Save a set of settings and that way you could tell it to process every three in a folder at a time or some other method.  Possibly by photo number if the camera names them as xxxA, xxxB, etc.  I don't know how to do this, but I suspect it wouldn't be so difficult.

Set it up - drop all of your multi-exposure pictures in the input folder, it spits out blended images to the output folder.   Come back after getting lunch and all of them are done.  Like your own automated mini-lab
Title: ZERO NOISE technique
Post by: Guillermo Luijk on April 05, 2008, 03:40:03 PM
Quote
Then I should do:

sRGB(gamma=1.0) -> XYZ
XYZ -> sRGB(gamma=2.2) ?

but if I am not missing something, in the end this means:
R' = R^(1/2.2)
G' = G^(1/2.2)
B' = B^(1/2.2)

which does not preserve the ratio between the colours, so tones change, don't they?

I am sorry for pushing up again this thread, but I did some checks to find out how the delinearization of a linear image happens in PS, and I am happy with the findings so I wanted to share.

1. I developed an image in DCRAW (linear output converted to sRGB)
2. I opened it into PS and converted it now to non-linear sRGB (PS should apply a 2.2 gamma)
3. I used a program I wrote some time ago that with Image 1 and Image 2 as input, calculates the RGB curves to go from Image 1 to Image 2. If the correspondence between both images is independent on each channel, the curve calculated will be exact to convert Image 1 into Image 2. Otherwhise it will just be an approximation.

Well, the curve calculated was this (see RED plot):

(http://img528.imageshack.us/img528/7708/namibia2bmpcurig7.gif)
RED: PS application of gamma 2.2
BLUE: pure 2.2 gamma

Exactly the same for the 3 RGB channels. That means the proper way to apply gamma is the easiest possible! good news. Probably you were already telling me this guys, but It was not clear to me.

I then calculated a pure 2.2 gamma curve to check if the curve that PS applied is a perfect gamma:

R'=R^(1/2.2)
G'=G^(1/2.2)
B'=B^(1/2.2)

R,G,B normalised values [0..1]

And it is was plotted in BLUE colour in the previous graph. It's very close to what PS did, just PS seems to lift deep shadows a bit less than the pure gamma curve. But the approximation is very good so I will use those simple formulas in my program and with the maximum floating point precision, no matter if it's a bit slow.

To allow the user to choose to apply the gamma before the final TIFF file is generated is important to improve a lot the robustness in the shadows and the maximum achievable DR expansion, which now can be greater than 16 f-stops!


BR
Title: ZERO NOISE technique
Post by: cedricb on May 07, 2008, 10:44:06 AM
Hi GLijk,

I'm a Java/C software developer. I'm just wondering if you could send me the main source code? So I could write a tools which can be used on every platform. I've tried to use wine on Linux with no success...

Or if you want I could be at your service to produce a cross platform tools instead of your VB software...  I can be your dev monkey!  

Please let me know.

Regards,
Ced.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on May 07, 2008, 09:41:22 PM
hi cedricb, it seems some C developers have got a lot of interest in writing Zero Noise in a more proper way in a Spanish forum; I have encouraged them to forget about developing the input RAW files but to output a DNG 16-bit RAW file. Any help with the DNG format (we just need the needed routines from the DNG SDK to build a 16-bit DNG file from the partial RGGB data) is VERY WELCOME.

Moreover we plan to write first a GUI for DCRAW; not just another front end for it but a very technical RAW developer (with a philosophy close to Gabor's RAWnalyze) to really exploit DCRAW's capabilities so as some new features.
It will focus on:
- A very precise display of the image
- Total control of pure RAW development tasks not caring at all about those (curves, saturation,...) that are best done in PS
- Before/After comparision splits for any of the settings

A very basic approach of the GUI and functions could be:

(http://img527.imageshack.us/img527/4261/guiiu7.jpg)

(http://img178.imageshack.us/img178/4065/gui2fr2.jpg)


If you know about DNG please let me know.

BR

PS: this is not related to the answer, but wanted to show how well DCRAW's highlight recovery performs with bright areas on skin. Left is the result using -H 2 (neutral) option, same result as with ACR/LR recovery routines. Right is the active tone emulation performed with -H 9 in DCRAW, not always works but here was fine (no PP at all in either of the recoveries):

(http://img293.imageshack.us/img293/9449/recupmh9.jpg)
Title: ZERO NOISE technique
Post by: MichaelEzra on May 08, 2008, 05:01:00 PM
GLuijk, I just tested v 0.91 and it worked great! (I had some problems with v0.9 before)
Title: ZERO NOISE technique
Post by: dwdallam on May 09, 2008, 07:45:07 AM
It would be great if we see a PS plugin for this great tool. If you could do something like that, surely you could sell it to a software developer and retire. lol

Nice work.

I'll bet the ACR guru who works for Adobe is already on it as we speak. I mean, why not?
Title: ZERO NOISE technique
Post by: Guillermo Luijk on May 09, 2008, 10:57:53 AM
Quote
It would be great if we see a PS plugin for this great tool.

what would be the advantage of having this program in the form of a PS plugin? people not using PS could not enjoy it, and anyway would offer no advantages since it uses DCRAW for the RAW development.
Title: ZERO NOISE technique
Post by: Wayne Fox on May 09, 2008, 03:40:49 PM
Quote
what would be the advantage of having this program in the form of a PS plugin? people not using PS could not enjoy it, and anyway would offer no advantages since it uses DCRAW for the RAW development.
[a href=\"index.php?act=findpost&pid=194602\"][{POST_SNAPBACK}][/a]

I agree that doing it as a plugin only may not be ideal., but, I wish all RAW developers would offer a plugin option so I could work inside of bridge and photoshop.  I use ACR most of the time just because of the simplicity of the workflow.  If I could load C1 or some other RAW processing software as a plugin (or file format module) to operate like camera raw I would most likely try them, for now the workflow is just too easy with ACR that I default to that most of the time.
Title: ZERO NOISE technique
Post by: MichaelEzra on May 09, 2008, 08:48:06 PM
I think the idea here is that Zero Noise could use some sort of plug-in architecture for use of different RAW converters, based on user's preference.

Another approach would be to have a raw output from Zero Noise, as was discussed before, and then any desired raw converter could be used:)
Title: ZERO NOISE technique
Post by: Andy M on May 19, 2008, 03:37:04 PM
Is the software available for Mac?
Title: ZERO NOISE technique
Post by: dwdallam on May 20, 2008, 03:22:19 AM
Quote
what would be the advantage of having this program in the form of a PS plugin? people not using PS could not enjoy it, and anyway would offer no advantages since it uses DCRAW for the RAW development.
[a href=\"index.php?act=findpost&pid=194602\"][{POST_SNAPBACK}][/a]

Why not both DCRAW and PS as a plugin?
Title: ZERO NOISE technique
Post by: Plekto on May 20, 2008, 01:48:16 PM
Because Adobe does its own funky ting when it converts/imports data and then does more "tweaking" with it when you save it back.

It's much easier to just keep it as it is - a stand alone app that does one thing better than any of the multi-tasking ones out there.
Title: ZERO NOISE technique
Post by: dwdallam on May 21, 2008, 02:31:10 AM
Quote
Because Adobe does its own funky ting when it converts/imports data and then does more "tweaking" with it when you save it back.

It's much easier to just keep it as it is - a stand alone app that does one thing better than any of the multi-tasking ones out there.
[a href=\"index.php?act=findpost&pid=196817\"][{POST_SNAPBACK}][/a]

Ah ok. I was thinking something else. That's why someone asked if it could be coded to DNG output? If so, yeah that would be fine.
Title: ZERO NOISE technique
Post by: Plekto on May 21, 2008, 08:21:16 PM
http://luminous-landscape.com/forum/index....showtopic=25484 (http://luminous-landscape.com/forum/index.php?showtopic=25484)

Specifically this.  Yes, adding more options for output is always a good thing.(I'm not a fan of "Photoslop" as you might gather.
Title: ZERO NOISE technique
Post by: dwdallam on May 22, 2008, 03:15:11 AM
Quote
http://luminous-landscape.com/forum/index....showtopic=25484 (http://luminous-landscape.com/forum/index.php?showtopic=25484)

Specifically this.  Yes, adding more options for output is always a good thing.(I'm not a fan of "Photoslop" as you might gather.
[a href=\"index.php?act=findpost&pid=197142\"][{POST_SNAPBACK}][/a]

I'm not a fan of any legalized monopoly, including Microsoft, Adobe, or Oil Companies, and Power distribution companies. I really do wish there were more options to both increase quality and to drive down price.
Title: ZERO NOISE technique
Post by: hassiman on May 26, 2008, 11:04:44 PM
Hi,

Has anyone here tried the really graet ENFUSE GUI front end BRACKETEER which is great at extending dynamic range and reducting noise by blending bracketed exposures.    If so how does it compare with ZERO NOISE and where can I get ZERO NOISE for MAC?
Title: ZERO NOISE technique
Post by: Guillermo Luijk on May 27, 2008, 05:25:16 AM
Quote
where can I get ZERO NOISE for MAC?
Nowhere, but if you would like to write Zero Noise for Mac, I will share with you all the algorithms.

Zero Noise is very demanding with correct image alignment, but regarding noise is very optimised, I would dare to say that noise cannot be reduced more than Zero Noise does. This is not because Zero Noise is wonderfully coded, just because of the way it works, selecting individually the less noisy pixels.
Title: ZERO NOISE technique
Post by: cedricb on June 03, 2008, 02:57:36 AM
GLuijk,

Can you post the link of the Spanish forum so I can have a look at the ZN rewrite.


Regards,
Ced.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on June 03, 2008, 05:51:18 AM
Quote
Can you post the link of the Spanish forum so I can have a look at the ZN rewrite.

There is no ZN rewrite yet, we are designing first our own RAW developer: Perfect RAW (http://www.ojodigital.com/foro/forumdisplay.php?f=125).
Title: ZERO NOISE technique
Post by: cedricb on June 04, 2008, 07:45:58 AM
I would like to use your ZN technique on Linux and for the time been there is no image editor which handles 16bits images (GIMP will do that in the future).

I don't really need a GUI to merge a set of RAW (I'll do with the default camera WB), so could you share your code for the exposure calculation and the blending?
I'm just wondering I can do the same thing (for the time been) with ImageMagick (http://www.imagemagick.org/script/index.php) and dcraw... Linux/Mac/Windows users should be able to use it...

With ImageMagick, you can blend two images with a percentage ratio (http://www.imagemagick.org/Usage/compose/#blend)
Title: ZERO NOISE technique
Post by: Guillermo Luijk on June 07, 2008, 07:16:13 PM
Quote
could you share your code for the exposure calculation and the blending?

sure, here you are:

exposure calculation:
Function CalcularExpRelativas() As Integer
    Const rUmbralMin As Double = 65536 / (2 ^ 6)    ' Ponemos el mínimo 6 diafragmas más abajo para asegurar 2 diafragmas completos de intersección
                                                    ' entre tomas con sobreexposiciones de hasta +4EV
    Const rUmbralMax As Double = 65536 * 0.9        ' Nos quitamos de encima la zona de comportamiento no lineal, 20% superior del rango dinámico
    
    Dim i As Integer, j As Integer, N As Integer
    Dim lX As Long, lY As Long
    Dim Color0 As GFL_COLOR, Color1 As GFL_COLOR
    Dim rSum0 As Double, rSum1 As Double

    On Error GoTo CalcularExpRelativas_Error

    CalcularExpRelativas = 0
    
    N = UBound(GflBitmap)
    SetStatus "Calculating relative exposure..."
    
    ' Cálculo de exposiciones
    ReDim rFactor(N)
    i = 1
    rFactor(i) = 1#     ' La primera imagen es la toma menos expuesta, la referencia final de exposición
    SetStatus EliminaRuta(sFileTIFF(iPos(i))) & ": " & _
        Round(1 / rFactor(i) * 100) / 100 & _
        " (+" & Round(Log(1 / rFactor(i)) / Log(2) * 100) / 100 & " EV)", ADD
    For i = 2 To N
        rSum0 = 0#
        rSum1 = 0#
        For lX = 0 To lWidth - 1
            For lY = 0 To lHeight - 1
                gflGetColorAt GflBitmap(i - 1), lX, lY, Color0
                gflGetColorAt GflBitmap(i), lX, lY, Color1
                
                If Gfl2Long(Color0.Red) >= rUmbralMin And Gfl2Long(Color0.Red) <= rUmbralMax And _
                    Gfl2Long(Color1.Red) >= rUmbralMin And Gfl2Long(Color1.Red) <= rUmbralMax Then
                        rSum0 = rSum0 + Gfl2Long(Color0.Red)
                        rSum1 = rSum1 + Gfl2Long(Color1.Red)
                End If
                If Gfl2Long(Color0.Green) >= rUmbralMin And Gfl2Long(Color0.Green) <= rUmbralMax And _
                    Gfl2Long(Color1.Green) >= rUmbralMin And Gfl2Long(Color1.Green) <= rUmbralMax Then
                        rSum0 = rSum0 + Gfl2Long(Color0.Green)
                        rSum1 = rSum1 + Gfl2Long(Color1.Green)
                End If
                If Gfl2Long(Color0.Blue) >= rUmbralMin And Gfl2Long(Color0.Blue) <= rUmbralMax And _
                    Gfl2Long(Color1.Blue) >= rUmbralMin And Gfl2Long(Color1.Blue) <= rUmbralMax Then
                        rSum0 = rSum0 + Gfl2Long(Color0.Blue)
                        rSum1 = rSum1 + Gfl2Long(Color1.Blue)
                End If
                
            Next lY
        Next lX
        
        If rSum1 = 0# Then
            SetStatus "Too wide exposure gap", ADD
            SetStatus "DONE", ADD
            CalcularExpRelativas = -1
            AvisoError ("Too wide exposure gap between " & _
                EliminaRuta(sFileTIFF(iPos(i - 1))) & " and " & EliminaRuta(sFileTIFF(iPos(i))))
            Exit Function
        ElseIf rSum0 > rSum1 Then
            SetStatus "Too narrow exposure gap", ADD
            SetStatus "DONE", ADD
            CalcularExpRelativas = -1
            AvisoError ("Too narrow exposure gap between " & _
                EliminaRuta(sFileTIFF(iPos(i - 1))) & " and " & EliminaRuta(sFileTIFF(iPos(i))))
            Exit Function
        Else
            rFactor(i) = rSum0 / rSum1 * rFactor(i - 1) ' Acumulamos factores y lo mostramos en pantalla
            SetStatus EliminaRuta(sFileTIFF(iPos(i))) & ": " & _
                Round(1 / rFactor(i) * 100) / 100 & _
                " (+" & Round(Log(1 / rFactor(i)) / Log(2) * 100) / 100 & " EV)", ADD
        End If
    Next i
        
    SetStatus "DONE", ADD
    
CalcularExpRelativas_Resume:
    DoEvents
    Exit Function
    
CalcularExpRelativas_Error:
    MostrarError ("CalcularExpRelativas")
    CalcularExpRelativas = -1
    Resume CalcularExpRelativas_Resume

End Function


blending:
Sub FusionarImagenes(sRuta As String)
    Const MAXINT65535 As Long = 65535
    Dim sResult As String
    Dim i As Integer, N As Integer
    Dim lX As Long, lY As Long
    Dim Color As GFL_COLOR
    Dim lTH As Long
    Dim rIGamma As Single

    On Error GoTo FusionarImagenes_Error
    
    N = UBound(GflBitmap)
    SetStatus vbCrLf & "Blending into a noise free image...", ADD
    
    ' REPLICAMOS CÓDIGO SEGÚN GAMMA SEA 1.0 Y OTRA PARA GANAR VELOCIDAD
    rIGamma = 1 / (frmMain.hscGamma.Value / 10) ' 1/Gamma
    
    ' Tomamos el color del píxel de la toma más expuesta que cumpla las condiciones
    lTH = Round(MAXINT65535 * frmMain.hscTH / 100)   ' Umbral de fusión

    If rIGamma = 1# Then
        For lX = 0 To lWidth - 1
            For lY = 0 To lHeight - 1
                i = N
                gflGetColorAt GflBitmap(i), lX, lY, Color
                ' Bucle para elegir la imagen que prevalecerá
                Do While i > 1 And _
                    (Gfl2Long(Color.Red) > lTH Or Gfl2Long(Color.Green) > lTH Or Gfl2Long(Color.Blue) > lTH)
                    i = i - 1
                    gflGetColorAt GflBitmap(i), lX, lY, Color
                Loop
                ' Solo corregimos valor si no hemos recurrido a la toma menos expuesta
                If i > 1 Then
                    Color.Red = Long2Gfl(Round(Gfl2Long(Color.Red) * rFactor(i)))
                    Color.Green = Long2Gfl(Round(Gfl2Long(Color.Green) * rFactor(i)))
                    Color.Blue = Long2Gfl(Round(Gfl2Long(Color.Blue) * rFactor(i)))
                    gflSetColorAt GflBitmap(1), lX, lY, Color
                End If
            Next lY
        Next lX
    Else
        For lX = 0 To lWidth - 1
            For lY = 0 To lHeight - 1
                i = N
                gflGetColorAt GflBitmap(i), lX, lY, Color
                Do While i > 1 And _
                    (Gfl2Long(Color.Red) > lTH Or Gfl2Long(Color.Green) > lTH Or Gfl2Long(Color.Blue) > lTH)
                    i = i - 1
                    gflGetColorAt GflBitmap(i), lX, lY, Color
                Loop
                'If i > 1 Then   ' Solo corregimos exposición si i > 1
                Color.Red = Long2Gfl(Round(MAXINT65535 * (Gfl2Long(Color.Red) * rFactor(i) / MAXINT65535) ^ rIGamma))
                Color.Green = Long2Gfl(Round(MAXINT65535 * (Gfl2Long(Color.Green) * rFactor(i) / MAXINT65535) ^ rIGamma))
                Color.Blue = Long2Gfl(Round(MAXINT65535 * (Gfl2Long(Color.Blue) * rFactor(i) / MAXINT65535) ^ rIGamma))
                gflSetColorAt GflBitmap(1), lX, lY, Color
                'End If
            Next lY
        Next lX
    End If

    ' Guardamos imagen final generada
    sResult = "ZN_" & Format(Time, "hhmmss") & "_" & _
        Sust(frmMain.cmbProfile, " ", "") & "_G" & Sust(1 / rIGamma, ",", ".") & ".tif"
    SetStatus "Saving result as " & sResult & "...", ADD
    GuardarGflBitmap GflBitmap(1), DimeRuta(sRuta) & sResult
    
    ' Liberamos las imágenes cargadas
    For i = 1 To N
        CerrarGflBitmap GflBitmap(i)
    Next i
    
    SetStatus "DONE", ADD
    Beep
    
FusionarImagenes_Resume:
    DoEvents
    Exit Sub
    
FusionarImagenes_Error:
    MostrarError ("FusionarImagenes")
    Resume FusionarImagenes_Resume

End Sub
Title: ZERO NOISE technique
Post by: button on July 10, 2008, 09:01:11 PM
Hey Guillermo,

I've followed this thread over the past year, and I must say BRAVO!  I have two questions for you:

1) Does ZN v0.91 have your previously mentioned corrections for the Canon 40D?

2) When I open the noise corrected file (the "ZN" file generated by Zero Noise), it seems to have significantly lower resolution and detail than both the original RAW files and the TIFF files that your program creates prior to blending.  What am I doing wrong?

Thanks, and keep up the superb work!

John

Edit:  Ignore question #2.  There is no problem with your program's resolution!  Somehow, I had my resolution settings different in camera RAW (ACR) for the ZN files and the RAW images, even when opened at the same time.  Sorry for the confusion.  I would, however, very much appreciate an answer for question #1.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on July 11, 2008, 12:06:27 PM
Quote
1) Does ZN v0.91 have your previously mentioned corrections for the Canon 40D?
Not exactly corrected (since it's a fault of DCRAW's source code), but you can now in v0.91 easily solve the problem just by entering the right saturation value for your camera in the 'Saturation' text box.

I have detected 2 cameras so far that need to be corrected:
- Canon 30D: 3398
- Canon 40D: 13823

I am quitting my job in August and taking some kind of sabbatic year. I will devote a lot of time to getting used to code in C/C# and rewrite Zero Noise in this languages with another two guys introducing some needed improvements as the anti-ghosting and progressive blending. The idea is to produce a 16-bit DNG output file out of Zero Noise instead of a TIFF file so I again ask for help: if any coder is able to generate a DNG file from scratch using the Adobe DNG SDK just contact me.

We are already developing a new RAW developer based on DCRAW but with a powerful graphical interface and other new features for high precision RAW development (just development, no processing). If you want to track that project: Perfect RAW (http://www.guillermoluijk.com/software/perfectraw/index.htm).

BR
Title: ZERO NOISE technique
Post by: docmaas on July 11, 2008, 12:17:09 PM
Hi guillermo,

If possible pleasse continue with the tiff output as well.  Sigma cameras do not do dng.  

thanks,

Mike

Quote
Not exactly corrected (since it's a fault of DCRAW's source code), but you can now in v0.91 easily solve the problem just by entering the right saturation value for your camera in the 'Saturation' text box.

I have detected 2 cameras so far that need to be corrected:
- Canon 30D: 3398
- Canon 40D: 13823

I am quitting my job in August and taking some kind of sabbatic year. I will devote a lot of time to getting used to code in C/C# and rewrite Zero Noise in this languages with another two guys introducing some needed improvements as the anti-ghosting and progressive blending. The idea is to produce a 16-bit DNG output file out of Zero Noise instead of a TIFF file so I again ask for help: if any coder is able to generate a DNG file from scratch using the Adobe DNG SDK just contact me.

We are already developing a new RAW developer based on DCRAW but with a powerful graphical interface and other new features for high precision RAW development (just development, no processing). If you want to track that project: Perfect RAW (http://www.guillermoluijk.com/software/perfectraw/index.htm).

BR
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Title: ZERO NOISE technique
Post by: Guillermo Luijk on July 11, 2008, 01:14:35 PM
Quote
If possible pleasse continue with the tiff output as well.  Sigma cameras do not do dng.
Hi Mike, I didn't explain myself well: the RAW files to be fed into Zero Noise will be any vendor supported by DCRAW, just like now.
Only the output would be a DNG 16-bit RAW file free of noise with the optimal blending of the information contained in the original RAW files, and ready to be developed with your favourite RAW developer.

I wonder why no company has done this before; perhaps market researchs indicate that what people demand are programs where you just click a button to obtain a finished "HDR" image with no extra effort.

BR
Title: ZERO NOISE technique
Post by: button on July 11, 2008, 02:09:40 PM
Quote
I have detected 2 cameras so far that need to be corrected:
- Canon 30D: 3398
- Canon 40D: 13823
[a href=\"index.php?act=findpost&pid=207316\"][{POST_SNAPBACK}][/a]


Thanks very much for that.  Please continue the outstanding work!

John
Title: ZERO NOISE technique
Post by: feppe on July 11, 2008, 03:07:49 PM
Guillermo, how would you recommend combining Zero Noise Technique software with making panoramas (I'm using Autopano Pro)?

Example: I have a panorama with three shots. I shoot each of these 3 shots twice, bracketing 4 stops apart to use for Zero Noise, ending up with 6 shots.

I'd imagine it would be better to make the panoramas first, then do the blending in Zero Noise. My understanding is that ZN only reads RAW files, and since Autopano only produces TIFFs and PSDs, I'd have to find a way to convert those to DNGs. Or is there an easier way to approach this?

Or would you recommend doing the blending beforehand, and stitching afterwards? The potential problem with this is big panoramas where exposures are wildly different at the different edges of the final image.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on July 12, 2008, 09:06:33 AM
Quote
I'd imagine it would be better to make the panoramas first, then do the blending in Zero Noise. My understanding is that ZN only reads RAW files, and since Autopano only produces TIFFs and PSDs, I'd have to find a way to convert those to DNGs. Or is there an easier way to approach this?

Or would you recommend doing the blending beforehand, and stitching afterwards? The potential problem with this is big panoramas where exposures are wildly different at the different edges of the final image.

Forget about converting TIFF to DNG, it's conceptually wrong since DNG expected by ZN is a RAW undemosaiced file.

I think you can blend each of the three pairs in ZN (same WB is a must). If you shot the least exposed RAWs in each pair with the same exposure (aperture/shutter/ISO), they should be ready for Autopano straight out of ZN.
Otherwhise you can open the TIFF files and match their exposures with the 'Exposure' option of Photoshop or easier with a simple curve like:

(http://www.guillermoluijk.com/tutorial/dcraw/curvas_exp.gif)


Another option is to forget about ZN and blend the images yourself following this tutorial, which performs conceptually the same operations as ZN but into Photoshop: Yet another method to reduce noise with two exposures (http://jtrujillo.net/qpix/). This process can be applied after performing the 2 pano stitchings of 3 images each, as long as those stitchings match perfectly pixel to pixel.

BR
Title: ZERO NOISE technique
Post by: Plekto on July 14, 2008, 05:52:08 PM
Quote
I wonder why no company has done this before; perhaps market researchs indicate that what people demand are programs where you just click a button to obtain a finished "HDR" image with no extra effort.

Because since it is pure mathematical conversion, it essentially isn't able to be patented or made into a piece of software for them to sell at vastly inflated prices to professionals.(it's all about the money)
Title: ZERO NOISE technique
Post by: cedricb on August 15, 2008, 05:42:54 AM
GLuijk,

Sorry to be a pain but... I've just found some free time to carry on my Linux experiment...

What's the mathematical formula applied to the RGB matrix for the negative exposure compensation?


Regards,
Ced.
Title: ZERO NOISE technique
Post by: michaelnotar on August 18, 2008, 03:04:43 AM
very cool!

so how is this better than noise reduction software, like noise ninja? i am super happy with it after inspecting it with a critical eye.

an interesting note on my P25 back, i noticed if I OE a stop and pull it back in raw processing it get about 2 stops less noise. ie an exposure at iso 200 pulled back in brightness in raw has much less noise than if it was shot and processed normally at iso 50 the backs native iso.
Title: ZERO NOISE technique
Post by: cedricb on August 18, 2008, 08:22:42 AM
GLuijk,

Finally I've be able to produce a ZN effect with ImageMagick. I've compared "visually" with your ZN software and it "looks" the same.

Here is an example with the "lounge" images which uses the camera WB and a compensation of -3.93EV.

dcraw -v -w -W -o 0 -q 3 -4 -T hdr1.cr2
dcraw -v -w -W -o 0 -q 3 -4 -T hdr3.cr2
convert hdr3.tiff -negate negate.tiff
ec=$(echo 'e(l(2)*-3.93)' | bc -l)
convert hdr3.tiff -evaluate multiply $ec corrected.tiff
composite -compose CopyOpacity negate.tiff corrected.tiff mask.tiff
composite -blend 90 mask.tiff hdr1.tiff merge.tiff

...these should work for Linux/Mac and Windows...

The merge.tiff is a 16bits one so no gamma/contrast/brightness applied.

In term of tone mapping, have you got some magic curves which can be applied every where? :-)

I've replicated a similar Sigmoidal curve for the contrast but I don't know which settings you have used in your tutorial... contrast + mid-point
For the brightness, can you give me the settings for the curve?
Title: ZERO NOISE technique
Post by: BruceHouston on August 18, 2008, 10:26:08 AM
Thank you again for your work, Guillermo.

I for one am very appreciative of your interest and dedication to this.  I imagine that we will look back one day and recognize the significance of your contribution.  I predict that every serious DSLR will soon perform your algorithm in-camera.

Best regards,
Bruce
Title: ZERO NOISE technique
Post by: BruceHouston on August 18, 2008, 10:37:56 AM
Quote
Thank you again for your work, Guillermo.

I for one am very appreciative of your interest and dedication to this.  I imagine that we will look back one day and recognize the significance of your contribution.  I predict that every serious DSLR will soon perform your algorithm in-camera.

Best regards,
Bruce
[a href=\"index.php?act=findpost&pid=215795\"][{POST_SNAPBACK}][/a]

Otra cosita, Guillermo...  Aunque mi primer idioma es ingles, tambien soy fluente en el espanol.  Ando casi siempre atrasado en mi propio trabajo como abogado de patentes.  No obstante, estoy dispuesto de ayudarle con traducciones de espanol al ingles cuando lo necesite, ya con el acuerdo de que el trabajo probablemente no sea instantaneo.

Con estimo,
Bruce
Title: ZERO NOISE technique
Post by: Plekto on August 18, 2008, 06:44:34 PM
Quote
Thank you again for your work, Guillermo.

I for one am very appreciative of your interest and dedication to this.  I imagine that we will look back one day and recognize the significance of your contribution.  I predict that every serious DSLR will soon perform your algorithm in-camera.

He definitely should apply for a patent on the idea so that he's not going to get sued at some later date by some over-zealous manufacturer(or lose out on possible royalties)
Title: ZERO NOISE technique
Post by: cedricb on August 20, 2008, 09:11:54 AM
GLuijk,

I've been able to reproduce your exposure calculation in C with the ImageMagick API.

I'm just wondering if you can explain the colors min and max values:
min = 65536 / pow(2, 6);
max = 65536 * 0.9;

Another thing, is it possible to calculate the best blending ratio? for the time been I'm using 90%.


Regards,
Ced
Title: ZERO NOISE technique
Post by: Guillermo Luijk on August 21, 2008, 03:07:33 PM
Quote
I've been able to reproduce your exposure calculation in C with the ImageMagick API.

I'm just wondering if you can explain the colors min and max values:
min = 65536 / pow(2, 6);
max = 65536 * 0.9;

Another thing, is it possible to calculate the best blending ratio? for the time been I'm using 90%.
Ced


Hi Ced, nice to see you are achieving the same things on Linux.

I have gathered my answers to your questions:

1. Exposure correction down, in linear state, is as simple as multiplying each RGB level by a <1 factor. For instance let L be a 16-bit level that has to be corrected 1 f-stop down: OUT = L * 0.5

2. The contrast and bright curves I apply are always made by hand. The proper curves deeply depend on the image's histogram in front of you, and the desired result. I don't think a 100% automatic process is possible here. However some algorithm to get a curve with which to start should be possible (RAW developers calculate this curve).

3. The min = 65536 / pow(2, 6); max = 65536 * 0.9; were just my criteria. I thought values higher than 90% of sat could start to be non-linear in certain sensors. In the low end pow(2,6) ensures the program will not consider values falling in the 7th or lower f-stop (they are surely very noisy).

4. The best blending ratio of course is 100%, or nearly, but depending on how linear is your sensor to allow a lower value is recommended. 99% means any RGB value less or equal to 99% of saturation in a given image will be considered right.



Quote
estoy dispuesto de ayudarle con traducciones de espanol al ingles cuando lo necesite, ya con el acuerdo de que el trabajo probablemente no sea instantaneo.

That would be nice, I planned to translate the ZN tutorial this August but found no time. Would you like to translate some part of it? wait first cause a new version of the tutorial (in SP) is coming soon since I added new features.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on August 21, 2008, 03:25:12 PM
These days I could relax and add some features:This is the new GUI:

(http://img60.imageshack.us/img60/922/guiwx4.jpg)


Blending map (in black those pixels coming from the most exposed shot, gray medium exposure shot and white least exposed shot):

(http://img178.imageshack.us/img178/2672/mapapi9.gif)


200% crop of previous blending map (upper lamp): up without anti-ghosting nor progressive exposure (like ZN worked until now), down with 4px anti-ghosting radius plus 3px progressive blending radius.

(http://img178.imageshack.us/img178/7463/mapa2ej7.gif)


200% crop (ground lamp) on how ZN seeks most exposed areas to obtain them from less exposed shots. With real tone pixels coming from the most exposed shot, in green tones blending map showing pixels coming from the medium and least exposed shots, with a progressive area in the borders where information from more than one shot gets combined:

(http://img178.imageshack.us/img178/8541/greeniq9.jpg)


I will try to upload the update when it is 100% ready before my vacation (I will visit NY/Boston next month).

Salu2
Title: ZERO NOISE technique
Post by: BruceHouston on August 21, 2008, 04:20:26 PM
Quote
Hi Ced, nice to see you are achieving the same things on Linux.

I have gathered my answers to your questions:

1. Exposure correction down, in linear state, is as simple as multiplying each RGB level by a <1 factor. For instance let L be a 16-bit level that has to be corrected 1 f-stop down: OUT = L * 0.5

2. The contrast and bright curves I apply are always made by hand. The proper curves deeply depend on the image's histogram in front of you, and the desired result. I don't think a 100% automatic process is possible here. However some algorithm to get a curve with which to start should be possible (RAW developers calculate this curve).

3. The min = 65536 / pow(2, 6); max = 65536 * 0.9; were just my criteria. I thought values higher than 90% of sat could start to be non-linear in certain sensors. In the low end pow(2,6) ensures the program will not consider values falling in the 7th or lower f-stop (they are surely very noisy).

4. The best blending ratio of course is 100%, or nearly, but depending on how linear is your sensor to allow a lower value is recommended. 99% means any RGB value less or equal to 99% of saturation in a given image will be considered right.
That would be nice, I planned to translate the ZN tutorial this August but found no time. Would you like to translate some part of it? wait first cause a new version of the tutorial (in SP) is coming soon since I added new features.
[a href=\"index.php?act=findpost&pid=216527\"][{POST_SNAPBACK}][/a]


Guillermo: That would be nice, I planned to translate the ZN tutorial this August but found no time. Would you like to translate some part of it? wait first cause a new version of the tutorial (in SP) is coming soon since I added new features.

Bruce: Ok; please just email me the version that you want translated when you are ready, to: [email protected]

Best regards,
Bruce
Title: ZERO NOISE technique
Post by: cedricb on August 22, 2008, 05:10:48 AM
GLuijk,

Thank you for your reply...  

With the mask technique (negate of the over-exposed image to the alpha channel of the negative corrected over-exposed image) which is described in the PS tutorial, I don't get the same amount of perfect gradient in the spot light area in comparison of your ZN software.
My experiment produces the mask and blend the original image with a threshold ratio. So I don't thing it's exactly the same result than your software, or maybe I've done something wrong with the mask generation.
Can I upload the 16bits TIFF files (around 50M for each file) somewhere so you could have a look and let me know what's wrong?  

I've been using your "lounge" raw images for my test, so for your sensor which is the best blending ratio?

Could you shared your new algo for the "relative exposure calculation", so I can update my code.

Are you planing to release the code source when you hit version 1.0?  


Regards,
Ced.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on August 22, 2008, 05:46:54 AM
Quote
With the mask technique (negate of the over-exposed image to the alpha channel of the negative corrected over-exposed image) which is described in the PS tutorial, I don't get the same amount of perfect gradient in the spot light area in comparison of your ZN software.

My experiment produces the mask and blend the original image with a threshold ratio. So I don't thing it's exactly the same result than your software, or maybe I've done something wrong with the mask generation.
Surely they will never be 100% the same since there are always differences in implementation and rounding values. The important thing is if the solution works and provides a good result.

I have introduced progressive blending since just a small radius: 2 or even 1, will produce transition areas of 2+1+2=5 or 1+1+1=3 pixels wide with a smooth gradation between the images, usually enough to produce a soft effect in the border areas but still keeping most of the pixels genuine, i.e. coming from just one image to be optimum in noise reduction and avoid any loss of sharpness. In my example 98,6% pixels were kept genuine.


Quote
I've been using your "lounge" raw images for my test, so for your sensor which is the best blending ratio?
The 350D saturates at 4095 what makes me think (this is just an hypothesis) that its ADC actually clips the analogue output from the ISO amplifier making 350D's RAW files very linear up to saturation (at the cost of losing some highlight information captured by the sensor of course) because they have actually already been clipped to some threshold. That's why we can be very demanding with those sample images where very high thresholds can be set for blending.

I am not sure if other cameras where saturation does not reach the maximum of the RAW file range (for instance the 5D and 400D sat points are around 3500) are so linear close to saturation so they would need a lower threshold. The optimum threshold value cannot be calculated since it's hardware dependant; I have a feeling it could be kept very high for most situations but everyone should check how his camera works. I only have my modest 350D to do tests and it shows a very linear response (http://www.guillermoluijk.com/article/anavsdig/curvaloglog350d.gif) in the whole range up to saturation.


Quote
Could you shared your new algo for the "relative exposure calculation", so I can update my code.

Are you planing to release the code source when you hit version 1.0?
That new alg is still just in my mind, but it consists in calculating an accumulative array of relative exposures. For each pixel pair, the relative exposure is calculated, weighted by the level of exposure of those 2 pixels, and then fed into the array with the index according to the relative exposure calculated. In the end we just calculate the median of the statistical distribution obtained. I think it will work fine.

I will keep the new code secret (there is not too much to hide anyway) since the plan in the end is to translate the entire code to a C/C# application with the possibility of a RAW DNG output that could be then developed on the user's favourite software. The two fellows that code in C are still on vacation, I am just starting with VS C#.

I insist again that if someone is reading this that can use the Adobe DNG SDK to produce a DNG file from scratch just contact me.


BR
Title: ZERO NOISE technique
Post by: Hening Bettermann on October 30, 2008, 04:46:14 PM
Hi Guillermo!

I am looking forward to use your promising software! After studying the english article, I have a question:

The white balance should be the same in both shots. Would it be sufficient to adjust this post capture in the raw state? The white balance is the one exposure parameter that I prefer the camera to do automatically, since I can not see how I can do it better.

Despite my Zero Spanish, I also tried to extract some information from the tutorial, based on the pictures. Concerning fig. 4, 5 and 6: Does Zero Noise require to define the white balance based on an area in the actual picture?

Kind regards - Hening.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on November 03, 2008, 10:36:44 PM
Quote from: Hening
Hi Guillermo!

I am looking forward to use your promising software! After studying the english article, I have a question:

The white balance should be the same in both shots. Would it be sufficient to adjust this post capture in the raw state? The white balance is the one exposure parameter that I prefer the camera to do automatically, since I can not see how I can do it better.

Despite my Zero Spanish, I also tried to extract some information from the tutorial, based on the pictures. Concerning fig. 4, 5 and 6: Does Zero Noise require to define the white balance based on an area in the actual picture?

Kind regards - Hening.

Hi Hening, the white balance in Zero Noise can be set:
- Camera: will take the camera's WB embedded in the RAW file. Not very recommended if you used auto, but you can try it and see what happens.
- Coeffs: linear multipliers for the RGB channels (not very intuitive)
- Preset: presets
- Patch: choose a rectangular or circle patch and WB will be calculated according to it. IF YOU SET THIS PATCH COVERING THE ENTIRE IMAGE, YOU WILL GET AN AUTOMATIC WB WITHOUT THE PROBLEMS THAT CAMERA'S AUTO WB CAN HAVE, so this could be a good option for you.

BR
Title: ZERO NOISE technique
Post by: Hening Bettermann on November 05, 2008, 07:44:13 PM
Hi Guillermo,

thank you for your reply. - I can not quite see how this solves the problem. Make the patch cover the whole image - which one? The zero or the +4? The problem (with the camera AWB) as I see it is that light may shift between the 2 shots - So I thought one could adjust the one of them to the other post capture in the raw state before merging?

Kind regards - Hening.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on November 06, 2008, 07:49:03 AM
Quote from: Hening
I can not quite see how this solves the problem. Make the patch cover the whole image - which one? The zero or the +4? The problem (with the camera AWB) as I see it is that light may shift between the 2 shots - So I thought one could adjust the one of them to the other post capture in the raw state before merging?
Any of the shots is OK, but the most exposed is recommended to set the patch since it will have less noise and WB calculation will be more accurate. Don't worry about its blown areas since they do not participate in the WB calculation. Once the multipliers have been calculated they will be applied to the two shots so WB will be fine.

Light in the scene should not shift between your shots, why? you have to shoot them one right after the other, not wait for an hour  

BR

PS: BTW we already found someone who can build a DNG RAW file from RAW data. A version of Zero Noise with a 16-bit DNG output free of noise is nearing. I.e. the user puts several RAW files and the program will mix them into a noise free RAW file that everyone will develop and/or tone map using his favourite software.
Title: ZERO NOISE technique
Post by: Hening Bettermann on November 06, 2008, 05:18:51 PM
Hi Guillermo!

Thanks for your answer!

>Light in the scene should not shift between your shots, why? you have to shoot them one right after the other, not wait for an hour  

I agree: light should not shift, but you know, up here in the North (Oslo), light is so unbehaved, it DOES shift, and it does not take it an hour to do so, it can do it i a split second!    A typical shooting situation for me is that I stand behind the tripod, one hand on the cable release, waiting for the sun to peep through the clouds!

If, on the other hand, I am lucky enough to catch the same light for 2 consecutive exposures, then what is wrong with auto white balance? I thought the problem was that the automatism would apply 2 different white balances to shots due to light shift? But I have no technical understanding of how the automatism works, and I am open to learn.

(So far, I am satisfied with the result: I remember a day when I was shooting in the same place from about noon into the afternoon. Viewed one at a time, the images looked all natural. However, viewed side by side, those taken near noon were clearly more blue than those taken later in the afternoon. So the automatism does - fortunately - not wipe out the natural color shift in daylight entirely.)

>PS: BTW we already found someone who can build a DNG RAW file from RAW data. A version of Zero Noise with a 16-bit DNG output free of noise is nearing. I.e. the user puts several RAW files and the program will mix them into a noise free RAW file that everyone will develop and/or tone map using his favourite software.

That is GREAT news, and CONGRATULATIONS!  

Hening.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on November 06, 2008, 06:18:36 PM
Hi Hening, automatic white balance can never balance equally two different images if there are spatial differences in hue between them, i.e. if not all 100% of the surface of the image changes equally in white balance from one situation to another which is the common case. That is why any automatic white balance algorithm can be considered 'best effort' for these kind of situations.

I don't recommend to use camera's automatic white balance in Zero Noise, but you can do it: just select automatic WB in your camera and set Camera's WB in ZN, and see if the result is fine.

You can alternatively try DCRAW's automatic white balance by setting -a in the DCRAW command line dialog box, and each RAW file will be developed with DCRAW's auto WB algorithm. I did it over my example scene and you can see some slight differences in white balance (when they all should be the same):

(http://img142.imageshack.us/img142/711/wbafd4.jpg)

When doing so it's however almost mandatory to set some progressive blending to avoid visible colour steps in the transitions:

(http://img84.imageshack.us/img84/8065/stepyh1.jpg)

BR
Title: ZERO NOISE technique
Post by: MichaelEzra on November 07, 2008, 07:50:06 AM
Guilermo, this is really great news!!!
Title: ZERO NOISE technique
Post by: Hening Bettermann on November 07, 2008, 01:08:56 PM
Guillermo, thanks for your reply and instruction. Hening.
Title: ZERO NOISE technique
Post by: button on November 23, 2008, 08:38:53 AM
Quote from: GLuijk
PS: BTW we already found someone who can build a DNG RAW file from RAW data. A version of Zero Noise with a 16-bit DNG output free of noise is nearing. I.e. the user puts several RAW files and the program will mix them into a noise free RAW file that everyone will develop and/or tone map using his favourite software.

Any idea when you'll have this new version ready?  I can't wait!

John
Title: ZERO NOISE technique
Post by: Guillermo Luijk on December 09, 2008, 10:33:47 AM
Quote from: button
Any idea when you'll have this new version ready?  I can't wait!
In the last two days I adapted Zero Noise to work with undemosaiced RAW data, and it worked fine (in fact it's even easier than making it work with demosaiced data). I have also improved the routines to calculate the relative exposure between the shots.

I have just sent the resulting RAW blend (18MB TIF) (http://www.guillermoluijk.com/download/rawvirtual.tif) (it's linear data, it will display very dark if not assigned to a linear gamma=1.0 profile in PS) to a colleage to embed it into a 16-bit DNG file just to offer the resulting noiseless high dynamic range RAW file here for download.

It will be a Zero Noise HDR virtual RAW containing a lossless unprocessed blending of two Canon EOS 350D RAW files shot 4 stops apart:
   ─ Standard non demosaiced DNG
   ─ Free of noise shadows
   ─ 16 bits equivalent bitdepth
   ─ 12 stops real dynamic range

This was the scene:

(http://www.guillermoluijk.com/tutorial/hdr/resultadolite6.jpg)

And these are the RAW histograms of the two original files and the resulting virtual RAW:

(http://www.guillermoluijk.com/article/virtualraw/histos.gif)

The program will take a bit longer to be ready.

BR
Title: ZERO NOISE technique
Post by: Ben Rubinstein on December 09, 2008, 12:23:19 PM
Quote from: GLuijk
In the last two days I adapted Zero Noise to work with undemosaiced RAW data, and it worked fine (in fact it's even easier than making it work with demosaiced data). I have also improved the routines to calculate the relative exposure between the shots.

I have just sent the resulting RAW blend (18MB TIF) (http://www.guillermoluijk.com/download/rawvirtual.tif) (it's linear data, it will display very dark if not assigned to a linear gamma=1.0 profile in PS) to a colleage to embed it into a 16-bit DNG file just to offer the resulting noiseless high dynamic range RAW file here for download.

It will be a Zero Noise HDR virtual RAW containing a lossless unprocessed blending of two Canon EOS 350D RAW files shot 4 stops apart:
   ─ Standard non demosaiced DNG
   ─ Free of noise shadows
   ─ 16 bits equivalent bitdepth
   ─ 12 stops real dynamic range

This was the scene:

(http://www.guillermoluijk.com/tutorial/hdr/resultadolite6.jpg)

And these are the RAW histograms of the two original files and the resulting virtual RAW:

(http://www.guillermoluijk.com/article/virtualraw/histos.gif)

The program will take a bit longer to be ready.

BR

Given that the present tiff's need an extremely strong curve, what would the advantage be of making a DNG given that unless you can apply a specific gamma curve (not in ACR at any rate), the image will be far too dark to work with in the  raw converter? I'm very excited by the idea of a DNG output from this incredible program but only if the gamma can be programmed to show up in the raw converter so we can use it.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on December 09, 2008, 12:59:48 PM
Quote from: pom
Given that the present tiff's need an extremely strong curve, what would the advantage be of making a DNG given that unless you can apply a specific gamma curve (not in ACR at any rate), the image will be far too dark to work with in the  raw converter? I'm very excited by the idea of a DNG output from this incredible program but only if the gamma can be programmed to show up in the raw converter so we can use it.
The image will not be far too dark to work in the RAW converter. In fact in this example, the exposure control of ACR gives more exposure correction than you really need (in Perfect RAW (http://luminous-landscape.com/forum/index.php?showtopic=28791) we set an exposure correction of up to +8EV, truly usable with real 16-bit RAW files like the ones Zero Noise will produce).
I opened here the least exposed source RAW file, which will define the RAW exposure of the blend output, and managed to completely lift the shadows with a +4.0EV adjustment:

(http://img240.imageshack.us/img240/1540/acrba8.jpg)


The advantage of a RAW output is that you can now feed it into your favourite development/tone mapping workflow based on RAW data (RAW developer, HDR program,...), while the TIFF output necessarily needed to go to Photoshop for tone mapping, and not everyone feels comfortable doing manual tone mapping.
This was a general complaint of some users who tried Zero Noise and felt lost to tone map such a dark image out of their preferred RAW developer (not my case BTW, I am fond of curves and with just two of them I can tone map most HDR images produced by Zero Noise, as explained in this tutorial (SP): Mapeo de tonos HDR (http://www.guillermoluijk.com/tutorial/hdr/index.htm)).

Now the only difficult part is to deal with high dynamic range scenes and tone map them. But this is not a flaw of the method or concept of Zero Noise, which never was intended as a tone mapping tool, this is simply an issue that everyone will have to face when trying to fit HDR information on a LDR device (computer screen, printed paper,...).

BR
Title: ZERO NOISE technique
Post by: button on December 09, 2008, 04:27:09 PM
Quote from: GLuijk
The program will take a bit longer to be ready.

Man, I can't wait!  Please let us know when it's ready    

John
Title: ZERO NOISE technique
Post by: Guillermo Luijk on December 10, 2008, 10:11:41 AM
Quote from: button
Man, I can't wait!  Please let us know when it's ready  
OK, I have been finally given the RAW file, please download it from: ZERO NOISE VIRTUAL RAW (http://www.guillermoluijk.com/article/virtualraw/index_en.htm) (English). Find the links to the original RAW files so as to the resulting virtual noiseless RAW after Fig. 9.

The result in DR is outstanding. Adjustments straight from ACR:

(http://www.guillermoluijk.com/article/virtualraw/resultado_lite.jpg)

This comparision demonstrates that none of the original RAW files were able by themselves to capture all the dynamic range:

SHADOWS COMPARED TO RAW 1 (100% crops):
(http://www.guillermoluijk.com/article/virtualraw/sombrasdespues.jpg)(http://www.guillermoluijk.com/article/virtualraw/sombrasantes.jpg)

HIGHLIGHTS COMPARED TO RAW 1 (50% crops):
(http://www.guillermoluijk.com/article/virtualraw/lucesdespues.jpg)(http://www.guillermoluijk.com/article/virtualraw/lucesantes.jpg)



BR
Title: ZERO NOISE technique
Post by: button on December 10, 2008, 07:35:52 PM
Quote from: GLuijk
OK, I have been finally given the RAW file, please download it from: ZERO NOISE VIRTUAL RAW (http://www.guillermoluijk.com/article/virtualraw/index.htm). Find the links to the original RAW files so as to the resulting virtual noiseless RAW under Fig. 9.
(English online translation available, icon left).

The result is outstanding.

I've played around with the virtual RAW DNG in ACR, and yes, the result IS outstanding.  This is a really big deal, at least for me, so you are to be commended for your time and generosity.  Now, I REALLY can't wait for the next version of ZERO NOISE!

John
Title: ZERO NOISE technique
Post by: button on December 11, 2008, 10:30:09 AM
Hey Guillermo,

You obviously have a strong understanding of digital imaging theory and application.  Given your impending release of ZERO NOISE VIRTUAL RAW, do you have any suggestions for tone mapping which will avoid the "HDR cartoon" look?   For example, when you open the virtual raw file that you have provided on your website, how do you go about making it aesthetically pleasing to your eye?  Would you be able to provide suggested tone mapping curves, perhaps in .xmp format (since camera raw/lightroom are popular), assuming a standard 4-stop gap between the source raw files?  If this is not feasible, then would you mind explaining the difficulties involved?

Thanks,
John
Title: ZERO NOISE technique
Post by: Guillermo Luijk on December 11, 2008, 12:41:58 PM
Quote from: button
You obviously have a strong understanding of digital imaging theory and application.  Given your impending release of ZERO NOISE VIRTUAL RAW, do you have any suggestions for tone mapping which will avoid the "HDR cartoon" look?   For example, when you open the virtual raw file that you have provided on your website, how do you go about making it aesthetically pleasing to your eye?

So far (I mean in the future I can change my mind), the only way to obtain really pleasant natural looking HDR scenes is doing manual tone mapping because the software routines are not intelligent enough yet to emulate eye behaviour. Talking about existing software, the only quite close to this IMO is Enfuse, which produces quite pleasant results and is probably the simplest of all the algorithms around (it just scores pixels on each of the input image according to brightness, saturation and contrast, and that scoring is the weight for a not too complicated blending process). But still I prefer to do it by hand.

I think a really good HDR algorithm should first analyse the scene, and try to 'understand' it, identifying blocks or elements that humans see as a whole in terms of luminance. For instance inside a room with a window facing outside, all what is inside the frame of the window should be identified as a unique block, and should be processed as such. Another block could be the walls. Next block could be the floor which has tiles which are quite darker than the walls, and much darker than the window, and so forth,... In this way eye behaviour emulation would be much more realistic than present programs that hardly identify entire 'blocks' but adjust very precisely local contrast on small portions of the scene.

In this case I just did a quick developing in ACR (I never use it), keeping exposure at about -0.2 or close, and lifting the shadows strongly with Bright and with the curve. Later already in PS I applied a final contrast 'S' curve and that's it. But as I said it was a quick tone maping, I didn't intend to do it fine (among other things my laptop has a terrible uncalibrated screen).

In this Tutorial HDR (http://www.guillermoluijk.com/tutorial/hdr/index.htm) I explain how I do it with just 2 curves:
1. Bright push up, with a blurred layer mask to protect the highlights.
2. Contrast 'S' curve.

These 2 curves have the property to be (sorry if this is not the proper English math term) monotonous rising. That means that with those curves you will never make some point A that was brighter than a given point B in the real scene, become less bright than B in the final image. This is something often happens in HDR software; sometimes you try to find out where the light was coming from, where the sun was, where the lamps, but global contrast is so flat and there is such absence of shades that you cannot.

BR
Title: ZERO NOISE technique
Post by: Jonathan Wienke on December 20, 2008, 12:40:27 PM
Quote from: pom
Given that the present tiff's need an extremely strong curve, what would the advantage be of making a DNG given that unless you can apply a specific gamma curve (not in ACR at any rate), the image will be far too dark to work with in the  raw converter? I'm very excited by the idea of a DNG output from this incredible program but only if the gamma can be programmed to show up in the raw converter so we can use it.


When processed as DNG, you won't need to apply super-strong curves. You're looking at a file that is still linear--the RAW converter has not applied any gamma curve yet. The DNG will process just like any other RAW, but with more highlight detail and less shadow noise.

Overall, a very good effort so far. I look forward to making HDR DNG files...
Title: ZERO NOISE technique
Post by: Plekto on February 14, 2009, 03:43:59 PM
I had to search for this again.  Could we get this made a sticky?
Title: ZERO NOISE technique
Post by: cedricb on September 25, 2009, 10:16:45 AM
Hi GLuijk,

I'm just wondering if you could explain in details how to make your layer mask for brightness ?

(http://www.guillermoluijk.com/tutorial/hdr/mascaras1.jpg)

Step 1: curve apply to the original image
Step 2: negate of what?
Step 3: how do you do that? make it white/transparent the shadows and midtones?
Step 4: do you apply a Gaussian of 5.8 ratio?

In term of the saturation, which value did you apply to your picture? do you use the same value every time with the same camera?

For the original image from ZN (figure 1), did you apply a gamma of 2.2 and a sRGB color space?


Regards,
Ced.
Title: ZERO NOISE technique
Post by: Guillermo Luijk on September 25, 2009, 10:37:45 AM
To create the layer mask for the Bright curve I do:

1. Go to the output image from ZN and do: Selection -> All, and then Edition -> Copy. With this a copy of the image is in the Clipboard
2. Now show the layer mask of the curve by clicking on the curve icon while keeping 'Alt' pressed. At that time the mask will be totally blank. Do now Edition -> Paste. This will paste the luminance of the image in the layer mask (greytones image).
3. Without leaving the layer mask yet do: Image -> Adjust -> Invert, so that the Bright curve will affect less the highlights and more the shadows (that are the ones we want to lift).
4. Now adjust levels on the mask layer to your like: clipping to pure white all the areas where the curve must work 100% (i.e. the shadows of the scene), and clipping to pure black the areas that are to be 100% protected (the highlights).
5. Finally do some gaussian blurring (5-6 px radius, depending on camera resolution) to preserve microcontrast detail.

BTW there is a Linux version (http://www.guillermoluijk.com/software/zeronoise/index.htm) working 4 times faster than the original, and a DNG output version is finally on the way.

(http://www.guillermoluijk.com/software/zeronoise/zero_linux.jpg)

The guy who translated the source code from VB6 to C++ is a C optimizer freak, and is doing a lot of improvements to my code to make it run faster. I hope we manage to do the DNG output version soon.

Regards
Title: ZERO NOISE technique
Post by: cedricb on September 25, 2009, 11:28:44 AM
Hi GLuijk,

That's a fast reply...  

I'm aware of that Linux version but there is no binary for 64bits...  with my custom shell script with ImageMagick, I don't have to apply a blending ratio: I'm overlaying a transparent mask with the exposure differences (2 masks with 3 images).

http://imagebin.ca/view/my5hgs.html (http://imagebin.ca/view/my5hgs.html)

so step 1 and 2; it's just making a difference between the image with the curve and the original image?

http://imagebin.ca/view/1ZgIxG4A.html (http://imagebin.ca/view/1ZgIxG4A.html)

step 3:

http://imagebin.ca/view/ZAS0hCE.html (http://imagebin.ca/view/ZAS0hCE.html)

Please let me know if that's correct?  

can I automate step 4? by detecting a kind of the luminance ratio?
Title: ZERO NOISE technique
Post by: Guillermo Luijk on September 25, 2009, 03:56:43 PM

The images don't display.
Title: ZERO NOISE technique
Post by: erick.boileau on September 25, 2009, 04:31:28 PM
Hi GLuijk  !
is it working for MAC (64 bits) ?
Title: ZERO NOISE technique
Post by: jmb on September 26, 2009, 01:23:28 AM
Hi Guillermo,

Quote from: GLuijk
BTW there is a Linux version (http://www.guillermoluijk.com/software/zeronoise/index.htm) working 4 times faster than the original, and a DNG output version is finally on the way.

Are you guys working on updating the windows version as well?

JMB
Title: ZERO NOISE technique
Post by: cedricb on September 26, 2009, 04:12:24 AM
I've updated the images link...
Title: ZERO NOISE technique
Post by: Guillermo Luijk on September 26, 2009, 05:49:07 AM
Quote from: jmb
Are you guys working on updating the windows version as well?
Definitively I'd like a DNG output version. I don't like the way DCRAW develops the RAW files from my 5D so I want to be able to fuse them in the undemosaiced domain and then take them noise-free into ACR.

Quote from: erick.boileau
is it working for MAC (64 bits) ?
Someone managed to run the Linux version in a Mac under Ubuntu, but there is no native Mac version yet.

Quote from: cedricb
I've updated the images link...
I think the best is you download this TIFF file (http://www.guillermoluijk.com/download/hdr.tif) from the tutorial and look at the mask layer. What you need to achieve is a mask that is dark in the highlights of the scene, pure white in the deep shadows of the scene, and  blurred to preserve local microcontast.

Regards
Title: ZERO NOISE technique
Post by: klane on September 26, 2009, 02:52:42 PM
Quote from: GLuijk
Definitively I'd like a DNG output version. I don't like the way DCRAW develops the RAW files from my 5D so I want to be able to fuse them in the undemosaiced domain and then take them noise-free into ACR.


Someone managed to run the Linux version in a Mac under Ubuntu, but there is no native Mac version yet.


I think the best is you download this TIFF file (http://www.guillermoluijk.com/download/hdr.tif) from the tutorial and look at the mask layer. What you need to achieve is a mask that is dark in the highlights of the scene, pure white in the deep shadows of the scene, and  blurred to preserve local microcontast.

Regards

Id love to have a native version for mac! Id pay for it.
Title: ZERO NOISE technique
Post by: cedricb on November 16, 2009, 10:01:10 AM
Quote from: GLuijk
I think the best is you download this TIFF file (http://www.guillermoluijk.com/download/hdr.tif) from the tutorial and look at the mask layer. What you need to achieve is a mask that is dark in the highlights of the scene, pure white in the deep shadows of the scene, and  blurred to preserve local microcontast.
Hi Gluijk,

I've been able to reproduce your brightness adjustments with ImageMagick. To produce the step 3, I've convert the ZN image (gamma 2.2) to the Rec601Luma colorspace. Then I've applied a threshold of 35% of luminance to produce a black and white mask (which I can overlay over the alpha channel of the negate gamma image).

(http://img134.imageshack.us/img134/8739/lumamask.png)

Do you think I could generate the optimum luminance threshold based on something from the image? histogram?

For the brightness and contrast curves, is possible to generate the different points based on the histogram of the image?

...last one, how do you perform/calculate your WB patch in ZN which I think you set the -r parameter of dcraw?
Title: ZERO NOISE technique
Post by: cedricb on November 19, 2009, 04:33:41 PM
If I want to use TuFuse to do the tone mapping. Do I need to have 5 images (1-2-3 2-3-4 3-4-5) and use the ZN technique to produce 3 images? ...or is there any way to produce the 3 images from the 3 catches?
Title: ZERO NOISE technique
Post by: Guillermo Luijk on November 24, 2009, 04:48:09 PM
Quote from: cedricb
If I want to use TuFuse to do the tone mapping. Do I need to have 5 images (1-2-3 2-3-4 3-4-5) and use the ZN technique to produce 3 images? ...or is there any way to produce the 3 images from the 3 catches?

You can fuse your RAW files in ZN, and then create several replicas in PS just pushing exposure up at 2EV intervals. Just make sure all areas of the scene get a correct exposure in some image in the set and TuFuse will work finely.

I requested the author of TuFuse (http://www.tawbaware.com/forum2/viewtopic.php?t=5507) to expand the autobracketing option in TuFuse to avoid this mess with ZN outputs.

Regards
Title: ZERO NOISE technique
Post by: cedricb on November 24, 2009, 05:45:33 PM
Thanks a lot, I've tried it with enfuse and works perfectly. Do you think, we should get a better result with: 0EV 1EV 2EV 3EV 4EV ?  ...difficult to see the difference!

Can you shed some light on this please?

Quote
how do you perform/calculate your WB patch in ZN which I think you set the -r parameter of dcraw?
Title: ZERO NOISE technique
Post by: Guillermo Luijk on November 24, 2009, 06:11:35 PM
Quote from: cedricb
Thanks a lot, I've tried it with enfuse and works perfectly. Do you think, we should get a better result with: 0EV 1EV 2EV 3EV 4EV ?  ...difficult to see the difference!

Can you shed some light on this please?
If it's difficult to see the difference you already gave the answer.
Title: ZERO NOISE technique
Post by: cedricb on December 01, 2009, 05:33:51 AM
A tribute to your tutorials using ImageMagick http://cbompart.wordpress.com/category/image-processing/ (http://cbompart.wordpress.com/category/image-processing/)

I hope you don't mind, I've used your lounge images so people can relate to your tutorials and compare. Please let me know if I need to add any copyright, etc.
Title: ZERO NOISE technique
Post by: NathanSoliz on December 08, 2009, 11:27:35 PM
I had to sign up for this forum in order to say thanks!
This is an amazing process and a wonderful applications.

I hope you make a lot off it and share with the world

I do have some questions since I'm still learning.
When you sat 4stops, you mean via your shutter speed? I have a Canon 20D and I stopped it for in AV mode, 4 clicks on my shutter. Is this right?
I'm a little fuzzy on the lingo.

Thanks,
Nathan Soliz.
Title: ZERO NOISE technique
Post by: Hoang on December 09, 2009, 01:04:49 AM
Quote from: NathanSoliz
I had to sign up for this forum in order to say thanks!
This is an amazing process and a wonderful applications.

I hope you make a lot off it and share with the world

I do have some questions since I'm still learning.
When you sat 4stops, you mean via your shutter speed? I have a Canon 20D and I stopped it for in AV mode, 4 clicks on my shutter. Is this right?
I'm a little fuzzy on the lingo.

Thanks,
Nathan Soliz.
If your camera is set to the default settings, each click should be 1/3 of a stop, so you'd need 12 clicks.
Title: ZERO NOISE technique
Post by: NathanSoliz on December 09, 2009, 12:29:03 PM
Quote from: Hoang
If your camera is set to the default settings, each click should be 1/3 of a stop, so you'd need 12 clicks.

Ok thanks, yes my camera's settings are set by 1/3 in the settings options.

So may I ask more?
I'm using Manual M42 lenses and some Nikon's on my Canon 20D. I set my F stop on the lens wide open (1.4f) and my 'shutter speed' is set to what I want to see in the end result.
Once I take that shot, for example... @ 1/160th, I then go down 12 clicks?

Hmmm I may have been doing it wrong then.
Title: ZERO NOISE technique
Post by: Plekto on June 28, 2010, 01:13:26 PM
I was wondering if the admins here could perhaps make this and a few other longer-running threads bookmarked/at the top so that they are easy to find?  I had to search for a couple of minutes to find it again, and if someone had joined in the last seven months, they'd not even know it exists.   This really is the best software that almost nobody knows about.
Title: ZERO NOISE technique
Post by: Craig Murphy on June 28, 2010, 06:28:36 PM
Is there a link to the current software?
Title: ZERO NOISE technique
Post by: feppe on June 28, 2010, 06:30:39 PM
Quote from: Craig Murphy
Is there a link to the current software?

There is in the OP; latest version (http://www.guillermoluijk.com/software/zeronoise/index.htm).
Title: ZERO NOISE technique
Post by: Craig Murphy on June 28, 2010, 07:04:36 PM
Thanks.  The biggest stumbling block to this is the cdraw download page.  Figuring out what  download link is correct for Windows xp sp3 is pretty confusing if not impossible unless you are way more knowledgeable of computer terminology than I am.
Title: ZERO NOISE technique
Post by: Erick Boileau on July 09, 2010, 08:01:21 AM
and nothing for MAC :-(
Title: ZERO NOISE technique
Post by: Guillermo Luijk on August 06, 2010, 04:43:06 AM
Quote from: erickb
and nothing for MAC :-(
Any Mac user who wants to run ZN can do it, it just takes some effort on his part.

In this thread (http://photography-on-the.net/forum/showthread.php?t=775795) a Mac user wrote a mini-tutorial about ZN using the Linux version (much faster and watermark free):

Zero Noise - The Basic Workflow
 
So here is Zero Noise in Linux, running on my Mac Pro under VMWare Fusion:
 
(http://kirkt.smugmug.com/Photography/Photo-of-the-Day/ZNWindow/700282284_HwTt8-XL.jpg)
(...)

Regards
Title: ZERO NOISE technique
Post by: Erick Boileau on August 06, 2010, 05:11:53 AM
Quote from: Guillermo Luijk
Any Mac user who wants to run ZN can do it, it just takes some effort on his part.

In this thread (http://photography-on-the.net/forum/showthread.php?t=775795) a Mac user wrote a mini-tutorial about ZN using the Linux version (much faster and watermark free):

Zero Noise - The Basic Workflow
 
So here is Zero Noise in Linux, running on my Mac Pro under VMWare Fusion:
 
(http://kirkt.smugmug.com/Photography/Photo-of-the-Day/ZNWindow/700282284_HwTt8-XL.jpg)
(...)

Regards

thank you Guillermo
Title: Re: ZERO NOISE technique
Post by: Hening Bettermann on January 15, 2011, 01:57:58 PM
Hi Guillermo

I was thrilled to read that ZN now outputs DNG's, and downloaded the sample image and the latest version of ZN, 1.1. It told me to download 0.9 first, then swap the .exe with the one downloaded as 1.1. Upon unpacking, that was named 0.9, too. I installed it anyway. When I tried to launch it, it said that this version was outdated, and prompted me to download the actual one. Where do I find that?

Kind regards - Hening.
Title: Re: ZERO NOISE technique
Post by: greenbean on January 19, 2011, 11:26:50 AM
It's true. All the links to the 1.1 update go to a download with the .09 version in the .zip

Anyway...Thanks for the awesome app Guillermo.
Title: Re: ZERO NOISE technique
Post by: MrMitch on January 19, 2011, 01:19:38 PM
Same here too, any updates or links ?
Title: Re: ZERO NOISE technique
Post by: MGH on January 20, 2011, 01:43:49 PM
Hi...Yes I´ve had the same problem as the last 3 posts. But also I can´t get V9.0 to work, it always crashes when it gets to "saving result as blend_Tif"  I´d love to get this to work and give it a try it seems an amazing program.

  Un saludo...
Title: Re: ZERO NOISE technique
Post by: Sterling22 on February 01, 2011, 11:38:43 PM
I replaced the exe file and get the v1.1 start button. But then I get a message that this version is out of date and to check for a new one. 1.1 is the latest version I can find. Is this program still available?
Title: Re: ZERO NOISE technique
Post by: Jean Spector on March 02, 2012, 08:23:32 AM
FWIW if you move the system clock a few months back (e.g. Mar 2011) the software runs fine.
Title: Re: ZERO NOISE technique
Post by: achrisproduction on May 20, 2012, 03:35:09 AM
Hel ;)o does it work on window 7 64bit?  thanks.   :)
Title: Re: ZERO NOISE technique
Post by: Jean Spector on May 20, 2012, 03:39:15 AM
Hel ;)o does it work on window 7 64bit?  thanks.   :)
I use it on (gasp!) Vista 64 with no issues - chances are it will work fine on Win7 64.

Jean