DNG color profile Color Tables generation from any target

[supercurio]

I'm about to start writing code for a brand new tool to generate DNG/DCP HueSatMap.

Neither X-Rite nor Adobe tool provide satisfying and consistent results in my experience, and both are also limited as their input is only 18 hard-coded colors.

Specific issues encountered with

Adobe DNG Profile Editor:

• Frequent "non-neutral gray patches ... significant color cast" error.
• Huge variations when applying or removing DNG BaseLineExposure (required when generating DNGs from smartphone camera RAW data)

X-Rite ColorChecker Passport software:

• No support of current DNG specifications (like GainMap Opcode for vignetting and color cast flat-field correction)

The software I'll write will accept XYZ for various illuminants or maybe spectral data directly as input for the patches, and charts of any dimensions.
Typically, first ones I'll use are the X-Rite Digital SG (140 patches, 14x10) and for comparison the CMP Digital Target 4 (570 patches, 30x19)

Do you know if any existing program already does that?
This is a tool I'll use as differentiator in my next product, the goal is get the calibration as good and consistent as it gets

[supercurio]

Okay I started writing the software described

After some initial experimentats, I'm a bit puzzled by the usage of HSV as color space for the profiles.
Typically, reducing saturation in HSV makes some colors a lot brighter as it is not perceptual.
I made those experiments on gamma-encoded RGB values tho so probably this won't be as much of an issue in DNG color profiles: they're applied on linear RGB data.

In practice, one example you'll encounter often because of that when you use Adobe DNG Profile Editor is blue or sky colors ending up too light.
I believe it doesn't have to if using more of what's the DNG spec, but this free tool does not and end up too limited.

Let me know if you have remarks or questions on this DNG calibration project. I can't wait to make my own profiles with it!

[ricgal]

Hi
I realise you started this post was started a while ago
I wondered if there is any software about for making DNG profiles for CMP or colorchecker SG targets?
thank you for your help

[Alexey.Danilchenko]

I wondered if there is any software about for making DNG profiles for CMP or colorchecker SG targets?

What's wrong with dcamprof which lives just here in a neighbouring thread and does exactly that?

[supercurio]

Hi ricgal!

I worked on other projects since and didn't make progress on that one yet.
It's perfectly possible to make profiles from any target indeed, sorry I didn't look into existing software however.

- And while I'm writing this, Alexey just gave a better answer

[xpatUSA]

I wondered if there is any software about for making DNG profiles for CMP or colorchecker SG targets?

Have you looked at this?

http://muscallidus.com/coca/

Ted

[AlterEgo]

Have you looked at this?

http://muscallidus.com/coca/

Ted

and did you ?  it is for ICC/ICM containers... not DCP (aka DNG profiles).