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Author Topic: DCamProf - a new camera profiling tool  (Read 694834 times)

torger

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Re: DCamProf - a new camera profiling tool
« Reply #100 on: May 06, 2015, 02:34:35 pm »

Currently the txt2ti3 always resamples to 5nm increments and 0-100 scale. I'll probably change to not resample, I just thought it would be easier to manually cut and paste if always in 5 nm, as a single file must have the same sampling.

The 0-100 scaling takes place because the file is supposed to look like an Argyll file and Argyll uses 0-100 as default scale for spectra, ie 100 means 1.0. When reading the .ti3 file DCamProf translates to 1.0 internally.

I suppose the problem is that you want to use the .ti3 file in some other software than DCamProf or Argyll and therefore want a 0-1 range? The "hack" with providing 0.01 as scale I guess works then, or do I need to add some feature?
« Last Edit: May 06, 2015, 02:37:28 pm by torger »
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kirkt

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Re: DCamProf - a new camera profiling tool
« Reply #101 on: May 06, 2015, 05:05:57 pm »

Hi Anders,

No problem- I am using it with dcamprof.  The problem was I exported from patch reader already scaled 0-100. I thought the txt2ti3 "-s" flag was a scaling value to use when computing the output. That is, because my values are already 0-100 I would want to use "-s 1.0" (don't scale). I guess the scale value is the scale rNge that exists in the in the input  file?

Either way, please don't wory about it!

Kirk
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torger

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Re: DCamProf - a new camera profiling tool
« Reply #102 on: May 07, 2015, 03:29:49 am »

Alexey, concerning the use of monochromator to make the best matrix profile I think you're in overkill space.

The thing is that to make a good matrix fit the matching task must not be too difficult. With modern cameras the CC24 is matched pretty good with a matrix, but that's because there are no extreme saturation colors. It can be seen that this good matching of the CC24 is made at cost of extreme colors.

If you instead try to make a matrix that will match also extremely saturated colors, with the help of a glossy target or indeed SSF and spectral data, you will get a much poorer match so the CC24-range of colors will suffer. You can try this with DCamProf now using the provided SSF example. Pure matrix profiles are best when optimized only for normal range colors, and for normal range colors a standard test target procedure will do just as good as SSF, possibly even better as I think it's harder to make an exact monochromator measurement.

I also know that SSF is not really something *all* manufacturers are using, some design the profiles the traditional way using targets and subjective tunings, so one cannot really say that SSF will make better profiles. It's probably easier to make dual-illuminant DCPs with better color temp predictions though as you can use the exact standardized illuminants though. Adobe is probably using SSFs.

That said I very much myself like to be able to measure SSF since once you have them you can make lot of interesting experiments, but I'm not really sure I would use an SSF-based profile for "production", haven't decided on that. It is possible to merge both SSF and traditional measurement into one .ti3 and make a profile from that too, but it's probably difficult as light sources need to match exactly.

But if I would only want a matrix profile, I would do it based on a test target.
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Alexey.Danilchenko

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Re: DCamProf - a new camera profiling tool
« Reply #103 on: May 07, 2015, 04:49:07 am »

Anders,

I have build a few of the matrix profiles from larger CC24 and passport and without further editing in daylight lighting they are hit or miss to say the least. Iliah makes cracking matrix profiles for RPP but as far as I know this involve a lot of manual colour correction past shooting profile based on sample images of known colours and reprofiling again.

The idea with spectral data for a sensor is to automate that manual colour correction step because all the expected responses for the needed colours of a scene can be generated and better fitting matrix produced. So the approach is far from useless to me.

The only decent matrix profiles I have managed to build from target and without post processing were made with QPCard 203 (a version of it not glued to the cardboard holder so was very easy to achieve needed flatness). Those still weren't perfect in some areas even on cameras with good colour separation (in that particular instance Kodak Pro Back with custom IR filter).
« Last Edit: May 07, 2015, 06:21:25 am by Alexey.Danilchenko »
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torger

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Re: DCamProf - a new camera profiling tool
« Reply #104 on: May 07, 2015, 05:19:34 am »

Ok, for that purpose having SSF will be very convenient of course.
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AlterEgo

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Re: DCamProf - a new camera profiling tool
« Reply #105 on: May 07, 2015, 10:06:57 am »

I also know that SSF is not really something *all* manufacturers are using, some design the profiles the traditional way using targets and subjective tunings, so one cannot really say that SSF will make better profiles.

who are those ? are they "manufacturers" of 3rd party raw converters of note or "manufacturers" of cameras that do supply either their own OEM software (or putting OEM dcp profiles in DNG files - like Ricoh/Pentax for example) ? it is interesting to know the names and compare vs others who then allegedly are using SSFs then, no ?

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torger

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Re: DCamProf - a new camera profiling tool
« Reply #106 on: May 07, 2015, 10:29:56 am »

who are those ? are they "manufacturers" of 3rd party raw converters of note or "manufacturers" of cameras that do supply either their own OEM software (or putting OEM dcp profiles in DNG files - like Ricoh/Pentax for example) ? it is interesting to know the names and compare vs others who then allegedly are using SSFs then, no ?

I get some things shared in confidence so in this case I did not want to share the names, you just have to trust me ;-)
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AlterEgo

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Re: DCamProf - a new camera profiling tool
« Reply #107 on: May 07, 2015, 10:53:41 am »

you just have to trust me
it is not about trust that they do, it is about who they are, so that we can see how they fare vs others really... but it seems that you are not going to tell, unless we get some help from CIA  :D !
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Alexey.Danilchenko

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Re: DCamProf - a new camera profiling tool
« Reply #108 on: May 07, 2015, 11:24:38 am »

it is not about trust that they do, it is about who they are, so that we can see how they fare vs others really... but it seems that you are not going to tell, unless we get some help from CIA  :D !

Anders simply may be bound by NDA
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torger

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Re: DCamProf - a new camera profiling tool
« Reply #109 on: May 07, 2015, 03:08:05 pm »

I have some ICC code half-working now, probably release next week. I just need to figure out some white balance confusion I'm having...

It will be matrix-only for linear pipelines only in the first release, so no Capture One. But I plan to support that eventually too.

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GWGill

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Re: DCamProf - a new camera profiling tool
« Reply #111 on: May 08, 2015, 01:39:09 am »

If you instead try to make a matrix that will match also extremely saturated colors, with the help of a glossy target or indeed SSF and spectral data, you will get a much poorer match so the CC24-range of colors will suffer.
As I understand it, to make a useful profile using sensor spectral measurements, you need to introduce a weighted model of real world colors, so that your matrix has least errors for "typical" use (where "typical" is set by your real world color weighting).
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torger

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Re: DCamProf - a new camera profiling tool
« Reply #112 on: May 08, 2015, 02:37:57 am »

As I understand it, to make a useful profile using sensor spectral measurements, you need to introduce a weighted model of real world colors, so that your matrix has least errors for "typical" use (where "typical" is set by your real world color weighting).

Yes that's probably a good idea, and you can do that with DCamProf using the -w parameter in the make-profile step.

I haven't had time to experiment that much with matrix-only profiles but it seems like the best "weighting" is actually to exclude those highly saturated colors and only include those that you expect to see in normal situations. It seems like the extreme colors are struggling too much in a different direction that it's impossible to make a reasonable match for those without clearly degrading the normal colors. Results will vary depending on camera though.
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torger

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Re: A "torture sample"
« Reply #113 on: May 08, 2015, 06:20:19 am »

The link to the IIQ doesn't work, and the greenblade spectrum text file lacks spectral data.

I'm using the provided patchtool text file examples to make the dcamprof make-target file parser a little bit more accepting on formats.

Hi Anders,

This image may be an interesting sample: http://echophoto.dnsalias.net/ekr/Articles/OLS_OnColor/SimpleCase/Data/20150107-CF046070_AdobeStandard.iiq
« Last Edit: May 08, 2015, 06:26:23 am by torger »
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AlterEgo

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Re: DCamProf - a new camera profiling tool
« Reply #114 on: May 08, 2015, 09:28:24 pm »

0.5.4 executable built for windows with mingw ( includes dcamprof.exe and libgomp_64-1.dll ) = https://app.box.com/s/l9w24lobqr2nr08439zxpzndcmvwkj70
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ErikKaffehr

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Re: A "torture sample"
« Reply #115 on: May 09, 2015, 03:10:25 am »

Hi Anders,

Sorry for the mess!

I put all info here: http://echophoto.dnsalias.net/ekr/Articles/ColorProfiles/Samples

Hopefully it works! For some reason a lot of files get protected for read from time to time.

I added a sample from my Sony Alpha 99, too.

Some background:

I had some discussion with Tim Parkin. He finds that the P45+ has inherently bad reproduction of chlorophyll green, making it yellowish. I don't disagree but I wanted to find out if it is a profiling thing or not.

So I bought a small flower, cut away some samples to measure with my ColorMunkey and shot it with strobe light. The reason a bluish purple flower was chosen was that I have seen it was a colour that easily turned into blue or reddish blue in conversion.

Best regards
Erik


The link to the IIQ doesn't work, and the greenblade spectrum text file lacks spectral data.

I'm using the provided patchtool text file examples to make the dcamprof make-target file parser a little bit more accepting on formats.

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Erik Kaffehr
 

torger

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Re: DCamProf - a new camera profiling tool
« Reply #116 on: May 09, 2015, 11:16:06 am »

Thanks, I will play with the files later.

The use of camera profiling and tools to do it is not so widespread so cameras and raw converters plus profiles is inseparable for most photographers. I think the camera is blamed many times when it is more about profile design, but if you do not have the tools or knowledge to make your own the color you get from the factory and bundled software is the final result.

Cameras do differ in separation ability though, but all cameras today, even older ones like the P45, has overlapping filters so they can separate colors rather well within their noise limits. So I think it is more up to profile design than many may think.

That chlorophyll green becomes yellowish can definitely be adjusted, but if there is metamerism no profile can fix it. The color separation test in DCamProf will show where color separation is weak, but SSF curves are required to do that test. I think I have curves for the H3D 39, same sensor, probably different IR filter though. I shall play around with those and see what I find. The builtin database kuopio-natural has leaves of many kinds, and there are more databases to find online.

I know Tim thinks the SMI measure (which dxo shows) correlates well with actual performance, but I am less sure about that when you have LUT profiles. More testing is required before I could form my own view though.

A camera with poor SMI will likely have better color separation ability in some color ranges than an ideal camera (a camera where SSF = observer CMF), and that could be greens.
« Last Edit: May 09, 2015, 11:26:00 am by torger »
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AlterEgo

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Re: DCamProf - a new camera profiling tool
« Reply #117 on: May 09, 2015, 01:49:21 pm »

That chlorophyll green becomes yellowish can definitely be adjusted, but if there is metamerism no profile can fix it.
what if you can move the color from the area of metameric failure with some filters though... for a particular scene
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Tim Lookingbill

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Re: A "torture sample"
« Reply #118 on: May 09, 2015, 05:05:37 pm »

I had some discussion with Tim Parkin. He finds that the P45+ has inherently bad reproduction of chlorophyll green, making it yellowish. I don't disagree but I wanted to find out if it is a profiling thing or not.

Best regards
Erik

From the excellent looking images I've seen of your work off the P45+, Erik, I've noticed they do come off as having a slight green (more like an ashen blueish green) bias with a light hand on saturation. Remember my suggestion of applying a luminance/saturation increase with Hue/Sat tool in Photoshop on your gallery exhibit image of the sunlit green knoll with the background mountains you linked to in the LuLa Coffee Corner forum?

For me adaptation working too long on a landscape with a magenta-ish blue sky (cobalt blue has a magenta element) requires constant retweaking of WB to get the right looking green. I do know from years of examining sunlit green plants that the sunlit portion of a non-waxy, midtone green leaf/grass does have a yellowish bias, but ACR/LR's exact hue that makes it look right requires very gradual adjusts due to the cyan portion of the green that can make shadows appear too cool which invokes the adaptive effect of seeing green highlights as warm or a thalo green.

To filter this cyan requires moving toward magenta which slightly warms up green highlights but with a much different hue. I would never let my custom DNG profile fix this because it made the greens look a slightly dull yellowish orange green. And I didn't like moving temp slider toward blue because it desaturates everything.

After a long WB edit with ACR4.4 profile I'ld walk away and come back to see I'ld made everything too green because I kept trying to get the cyan in the green tint slider to freshen up the green. So I went back to As Shot WB (returned tweaked 0 back to +6 to +10 toward magenta), selected the custom DNG profile, walked away, took a break, came back and it looked perfect. Hue changes applying the custom DNG profile is so subtle in warming up the greens that I never considered how much WB affects the overall perception of color cast. I think one has to consider color constancy in the mix of things rather than attributing it to metamerism.

I mean I had trouble getting the right green hue shooting Live Oak trees that I did a google image search and found WB and greens all over the map...

https://www.google.com/search?newwindow=1&hl=en&site=imghp&tbm=isch&source=hp&biw=1556&bih=941&q=live+oak+in+texas&oq=live+oak+in+texas&gs_l=img.3..0i8i30l2j0i24.3707.9093.0.9964.17.16.0.1.1.0.114.1335.15j1.16.0.msedr...0...1ac.1.64.img..0.17.1334.aZKWyeTORI4

None of them are correct looking.
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torger

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Re: DCamProf - a new camera profiling tool
« Reply #119 on: May 10, 2015, 06:20:22 am »

I just became aware that Argyll's printtarg can output chart files, that is it's probably really easy to make your own targets if you have a good inkjet printer and a spectrometer to measure it. I shall test and update the docs accordingly. I think an inkjet print will have at least as good spectral qualities as an IT8 target on photo paper.

Maybe I'll add a target generator later on as Argyll's targen is more tailored for printer and scanner targets.
« Last Edit: May 10, 2015, 06:34:18 am by torger »
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