Xrite Color Profiles ?

Started 10 months ago | Discussions thread
Xasan Senior Member • Posts: 1,092
Re: Fit algo
1

Jack Hogan wrote:

You make many good points Xasan, exposing that routine for what it is, a quick proof of concept.

Wasn't my intention to be critical at all.

Some more thoughts if I may (for you, or for somebody who wants to use your code):

1. maybe to exclude cyan patch from fitting. it doesn't fit sRGB

2. maybe to use patch 20 for normali9zation, it is the most 'neutral' one

3. maybe not to use any of patches 19, 21 to 24 for fitting, neutrals may become over-weighted if all the near-neutral patches are included

4. (if using sRGB) finding camera RGB to sRGB matrix directly, using recommended sRGB values as the reference, proved to be a good approach.

As is, your code remains a very practical one. I always amaze at how overrated and hyped are so-called professional profilers.

Differences can be due to a number of factors, including minimization criterion (average de2000 in the article I believe) and the fact that its complex nature can make the solution multimodal, hence the Normal equation seed to get in the ballpark.

I see.

Using better minimization algorithms helps (I've switched to lsqnonlin since then and Iliah suggests others with inertia).

I am currently on the road and away from my computer. If you would like to discuss this further send me a message via the about page on Strolls and I'll catch up with you next week.

Jack

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