We can have both. The contrast algorithm for color images is: 1. RGB -> HSI. 2. Apply histogram equalization to I. 3. HSI -> RGB.
Step 2 can be replaced by another contrast modification algorithm that does take parameters, unlike histogram equalization. The only question left is, which contrast formula do we use: 1. out = (in - average) * contrast + average 2. out = pow(in * pow(pivot, 1.0 / contrast - 1.0), contrast) I have tested 1) for grayscale and color images and it is not bad, gives good results. Malcolm's formula 2) is probably better, but have not tried it. Chris I would suggest we transfer the contrast conversation in the "Contrast" topic started. Also, the contrast algorithm will need color space conversions, for which I don't know yet if I should write them or maybe I could use something already existing. Not sure if Jeremy has those in OpenColorIO. On the other hand I think we can merge the histogram functions in few day, they are really very simple. Stefan
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