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Author Topic: State of the art camera profiling software?  (Read 42041 times)

Tim Lookingbill

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Re: State of the art camera profiling software?
« Reply #20 on: March 08, 2015, 01:34:20 pm »

I don't think demosaicing has that effect, and I have never seen it. In RawTherapee you can select 9 different demosaicers vastly different from each-other and they all produce the same color, *except* if you have an aliasing issue. A plain color woven fabric which provokes aliasing can probably in some circumstances cause different global color result depending on demosaicer. But any color in an area which is not plagued by aliasing will be rendered the same with different demosaicers.

In fact I think the DNG Profile Editor doesn't do demosaicing at all, as you can't zoom to 100% there it doesn't have to, it just takes blocks of 2x2 pixels (so you have all three channels represented) and produce a quarter size image from that which is used for profiling.

I'm referring to the quality of color changes the editing tools have on the preview that is influenced by the static image formed by a demosiac algorithm.

For instance when I zoom in at 400% in CS5 ACR adjusting the color noise sliders and chromatic aberration selector to get rid of purple fringing on a richly golden autumn leaf I notice either the hue shifts slightly to green or is reduced in saturation. Sliding the Color Noise slider back and forth I can see the screen like subpixel pattern shift underneath very similar to what I saw changing the angles of process color halftone dot rosettes.
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torger

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Re: State of the art camera profiling software?
« Reply #21 on: March 08, 2015, 01:36:13 pm »

Yes I've got the sense that a standard 24 patch profile often have issues with high saturation colors, and it's easy to explain -- the target does not contain any really high saturation colors. I'm not 100% sure that it actually is the case though, I've not yet made a controlled test.

That it doesn't work for artificial lights at night is a different subject I think as that is typically narrow band sources and often mixed light, I don't think that problem can be solved at all. What you can do with camera profile is to render "accurate" color in a typical daylight color temperature range.

To narrow down the problem area one can look first at the reproduction case, ie fixed light condition (say D50), render as accurate colors as possible in that condition. When the best methods for that has been laid down one can further look into how those profiles behave in extreme light conditions.
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digitaldog

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Re: State of the art camera profiling software?
« Reply #22 on: March 08, 2015, 01:44:19 pm »

Yes I've got the sense that a standard 24 patch profile often have issues with high saturation colors, and it's easy to explain -- the target does not contain any really high saturation colors. I'm not 100% sure that it actually is the case though, I've not yet made a controlled test.
Which is why any armchair color scientists here should provide colorimetric evidence that 24 patches from the MacBeth is problematic to Thomas Knoll and Eric Chan at Adobe and James Vogh at X-rite who I know would find this valuable. I worked with X-rite while they developed a number of targets for camera profiling and I'm certain such actual evidence would be something those companies would love to see proven.
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torger

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Re: State of the art camera profiling software?
« Reply #23 on: March 08, 2015, 01:46:00 pm »

I'm referring to the quality of color changes the editing tools have on the preview that is influenced by the static image formed by a demosiac algorithm.

Ah okay, I misunderstood. Good points, noise reduction and defringing etc can certainly have an effect on color. I think it's outside the scope of a profile to correct for that though.
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Tim Lookingbill

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Re: State of the art camera profiling software?
« Reply #24 on: March 08, 2015, 01:47:16 pm »

Which is why any armchair color scientists here should provide colorimetric evidence that 24 patches from the MacBeth is problematic to Thomas Knoll and Eric Chan at Adobe and James Vogh at X-rite who I know would find this valuable. I worked with X-rite while they developed a number of targets for camera profiling and I'm certain such actual evidence would be something those companies would love to see proven.

Me too.

I didn't know you were an armchair color scientist, Andrew?

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digitaldog

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Re: State of the art camera profiling software?
« Reply #25 on: March 08, 2015, 01:51:27 pm »

I didn't know you were an armchair color scientist, Andrew?
I'm not in real life or on TV. If you can find any post I've ever made, anywhere on the net that I claim to be, you win a big prize.
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Tim Lookingbill

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Re: State of the art camera profiling software?
« Reply #26 on: March 08, 2015, 01:57:15 pm »

Ah okay, I misunderstood. Good points, noise reduction and defringing etc can certainly have an effect on color. I think it's outside the scope of a profile to correct for that though.

Everything about profiling is unfolding on the front end at the source as the sensor response is measured and "dealt" with on the final back end according to some color standard model reference.

But no one knows what the results will be when you start editing a wide range of images that are formed by this front to back standard  process viewed and judged on a display. Golden autumn leaf my be slightly on the green side but how would one find in this complex process the cause of it when all the other colors look fine or correct.

Good luck to you investigating this. You've got your work cut out for ya' for sure. It's mind boggling how well all of this works as it does.
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torger

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Re: State of the art camera profiling software?
« Reply #27 on: March 08, 2015, 02:07:27 pm »

Which is why any armchair color scientists here should provide colorimetric evidence that 24 patches from the MacBeth is problematic to Thomas Knoll and Eric Chan at Adobe and James Vogh at X-rite who I know would find this valuable. I worked with X-rite while they developed a number of targets for camera profiling and I'm certain such actual evidence would be something those companies would love to see proven.

As far as I understand Adobe doesn't use the Adobe DNG Profile Editor for their own in-house profiles. I've heard that they use monochromator and custom software, but I'd love to know more details about it. The bundled color rendition with raw converters has become a competing factor though, so I'd guess it's a little bit of a secret how they do it, just like for Phase One and in the medium format industry as a whole whose color rendition in their own raw converters is a major selling point.

I'll try to devise an experiment to prove that the 24 patches is problematic, or even better prove that it is not so we all can relax :). I've not yet figured out how to do it though, any suggestions are welcome of course. If there is a problem it can be hard to differ between if the problem is too few patches, or the problem is that the color checker is not on spec.

Clearly some think that you can do better than those classic 24 patches (it was designed in the 70's) as there are other manufacturers with other targets with more patches and/or more saturated patches, but maybe they're just trying to sell on the usual "more is better" without actually being better in practice. I don't know (yet).
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digitaldog

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Re: State of the art camera profiling software?
« Reply #28 on: March 08, 2015, 02:15:53 pm »

Clearly some think that you can do better than those classic 24 patches (it was designed in the 70's) as there are other manufacturers with other targets with more patches and/or more saturated patches, but maybe they're just trying to sell on the usual "more is better" without actually being better in practice.
Agreed, clearly they do. And as yet, no evidence to supply to either company and hence my suggestion.

Clearly if someone's goal is to sell us a target, it's in their best interest to convince us more/different patches are better. I'm pretty sure nothing would make X-rite happier than to sell people another target.
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torger

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Re: State of the art camera profiling software?
« Reply #29 on: March 08, 2015, 02:59:01 pm »

Another comment regarding the available profile editors.

When it comes to subjective tuning Adobe's own doesn't allow "hue/saturation twists", ie lightness-dependent adjustments. For example it's common that a subjective profile warm up lighter reds and cool down darker reds. I think increasing saturation in shadows is also common. Adobe's own bundled profiles have plenty of this type of hue twists, but the tool they distribute (Adobe DNG Profile Editor) don't allow that type of edits unfortunately.

I looked at QPCard documentation, and it while it supports edits it too seems to be limited to 2D adjustments.

I don't know about the X-rite software.

In all it seems like currently available software is very limited in terms of subjective edits. How to increase or decrease color separation in a certain color range? Cool down shadows, warm up highlights etc.

I do like the concept more of having a neutral twist-free profile and then use the raw converter tools to do the subjective color edits, however most raw converters are designed such that making the really subtle adjustments like done in profiles is not possible to do with the raw converter color tools, and even if you can it sort of clutters the interface when you're doing further edits, so I do see a point of having some subjective adjustments in the profile too.

It seems like currently the possibility to do advanced subjective edits is only available to manufacturers using their own custom in-house software, unless I've missed some software (or feature in a software).
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digitaldog

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Re: State of the art camera profiling software?
« Reply #30 on: March 08, 2015, 03:00:29 pm »

It seems like currently the possibility to do advanced subjective edits is only available to manufacturers using their own custom in-house software, unless I've missed some software (or feature in a software).
The question I'd have is this: can you apply these edits using tools above the camera calibration pane (using Adobe converter as our example)?
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torger

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Re: State of the art camera profiling software?
« Reply #31 on: March 08, 2015, 03:38:18 pm »

Okay, google finally helped me find what I've thought would exist out there -- a commercial system for measuring the CFA of the camera.

The german company Image Engineering http://www.image-engineering.de has a product called camSpecs (hardware and software bundled) where you can measure the CFA. It's been discussed briefly in this forum before. It's quite smart, instead of using a monochromator and having to shoot like 80 pictures in 5nm bands they have a standard slide projector with filter narrow band filter slides so you sample several bands per picture. They have a never LED-based "active test chart" in the "camSpecs express" product.

However it's very limited in terms of profile creation, it's more of a system for making DxOMark type of measurements. The only thing you can make in terms of profile is to create a basic color matrix, no LUT stuff, and no ICC or DNG profile creation. So it's still not a complete profiling system.

The price? €9750, plus €2800 for the calibration device, plus VAT. A bit steep considering you'd still have to write your own profile making software :)

Their reference page contains companies like Canon, Nikon, Adobe, Fujifilm, Foveon etc, so I imagine that some of these systems are used by some of these companies when making profiles, but not without additional software...
« Last Edit: March 08, 2015, 04:06:06 pm by torger »
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AlterEgo

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Re: State of the art camera profiling software?
« Reply #32 on: March 08, 2015, 03:55:07 pm »

As are the ICC apparently:
Using ICC profiles with digital camera images
http://www.color.org/whitepapers.xalter

ICC (organization) can say whatever they want - the reality is different... I guess you do not dispute that rawdigger + argyll based example was provided to you before, no ?
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torger

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Re: State of the art camera profiling software?
« Reply #33 on: March 08, 2015, 03:56:19 pm »

The question I'd have is this: can you apply these edits using tools above the camera calibration pane (using Adobe converter as our example)?

Lightroom has some crude camera calibration adjustments, and then it has a color tool where can make various adjustments by selecting hue, but you can't select "dark red" and make a hue adjustment and then select "light red" and make a different hue adjustment (or lightness/saturation).

With RGB curves you can make some of these effects but it's more difficult to work with.

The best and most flexible color edit tools in a raw converter I've come across is what's found in Capture One, with it's color editor you can make advanced selections. But I think there are still a few edits that is done in bundled color profiles you can't do in that color editor.
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Czornyj

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Re: State of the art camera profiling software?
« Reply #34 on: March 08, 2015, 04:01:12 pm »

Camera profile is a whole different animal than a printer profile. You need virtually infinite number of patches to make a camera profile, but so or so profile optimisation for some of these patches will distort the effect in case of other patches.

In the end of the day you'll came up to conclusion, that you can make quite a decent profile with a small number of patches, or can make a better profile optimised for specific patches, or you can play with as many patches as possible in an endless pursuit for the best compromise.
« Last Edit: March 08, 2015, 04:04:29 pm by Czornyj »
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AlterEgo

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Re: State of the art camera profiling software?
« Reply #35 on: March 08, 2015, 04:06:53 pm »

The original way of applying an ICC profile was to convert to TIFF from the raw converter (using the raw converter's default color) and then handle color management outside the raw converter entirely. This is where the bad reputation of ICC profiles comes from.

digitaldog intentionally writes FUD  ;) he is very well aware about the fact that icc profiles can be done from data not subjected to any color transforms

The DNG profile format is a lot easier to understand though, has floating point natively supported, and has more flexibility with dual illuminants and a pre-exposure and post-exposure LUT.

as noted ICC container can have many color transforms stored (multiple LUTs for example), so it is up to the raw converter to use that data (even ICC /organization/ does not approve) pre and/or port exposure...

Writing an ICC to DNG Profile converter software is indeed possible and I'm thinking about doing that, but what you will have to do then is to specify which raw converter the ICC profile was made for

no, you just can write ICC to DCP converter assuming that ICC will be done with for example rawdigger + argyll with the specific purpose of being fed to your converter afterwards - so you have control on how ICC was created and the work is less complex... and you get argyll's ability to work with any target or multiple targets or whatever... now if you want specifically use for example P1 profiles from C1 then I am not sure about legality ...

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AlterEgo

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Re: State of the art camera profiling software?
« Reply #36 on: March 08, 2015, 04:10:43 pm »

Which is why any armchair color scientists here should provide colorimetric evidence that 24 patches from the MacBeth is problematic to Thomas Knoll and Eric Chan at Adobe and James Vogh at X-rite who I know would find this valuable.
Adobe does not use this target to create their own profiles shipped with ACR/LR :) ... wonder why ?
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AlterEgo

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Re: State of the art camera profiling software?
« Reply #37 on: March 08, 2015, 04:14:09 pm »

Agreed, clearly they do. And as yet, no evidence to supply to either company and hence my suggestion.

Clearly if someone's goal is to sell us a target, it's in their best interest to convince us more/different patches are better. I'm pretty sure nothing would make X-rite happier than to sell people another target.

they are pretty much happy with the price vs market with xrite passport... specifically that 99% of their buyers do things like fill the frame with the said target and create profiles for a daylight...
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torger

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Re: State of the art camera profiling software?
« Reply #38 on: March 08, 2015, 04:21:47 pm »

no, you just can write ICC to DCP converter assuming that ICC will be done with for example rawdigger + argyll with the specific purpose of being fed to your converter afterwards - so you have control on how ICC was created and the work is less complex... and you get argyll's ability to work with any target or multiple targets or whatever... now if you want specifically use for example P1 profiles from C1 then I am not sure about legality ...

I was thinking about creating ICC profiles in a P1 workflow which means you get a P1 type of profile, not "steal" the bundled profiles to get the same look in lightroom, but well I guess that would be a side-effect, but it would certainly not be illegal to provide the tool. Great idea about using rawdigger+argyll though if that's possible...

However concerning software projects, the most interesting I've found so far is to buy a $1200 monochromator (or a $500 off ebay), to measure the CFA curves, and then make profiles based on that. As far as I can see that is the state of the art way to make reference profiles (which you then have some additional tool to make subjective tunings on). It's however not available to consumers as there is no software. To make software that makes something previously only available to manufacturers available to ordinary photo hackers would be super-cool... maybe I would find out that the monochromator/CFA method would be no more effective than a greg macbeth 24 patch color checker though, and then I would cry a bit ;)
« Last Edit: March 08, 2015, 04:23:44 pm by torger »
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Czornyj

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Re: State of the art camera profiling software?
« Reply #39 on: March 08, 2015, 05:33:20 pm »

maybe I would find out that the monochromator/CFA method would be no more effective than a greg macbeth 24 patch color checker though, and then I would cry a bit ;)

Exactly. I believe that monochromator saves time in a case of guys like Adobe color engineers, who need to find the best compromise for various objects SPD curves and lighting conditions.
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