I'm trying to automatically adjust color images taken with two bookscanner cameras to match, more or less, the colors of the same page as scanned by a calibrated flat bed scanner. Here are the two images (Full size tiff versions are in http://ucblibrary4.berkeley.edu/~apollo ... ick/colors
My idea was to use -level and -channel to adjust each RGB value as necessary to match the calibrated version. What I did was crop out a section of red, green, blue, and cyan from each image and a got the average RGB value from each of those 4 images.
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I naively thought that if the R channel of red_left.tif was off by 50 then the R channel of green_left.tif, blue_left.tif, cyan_left.tif would be off by about the same amount. But I can't see any rhyme or reason to how the channels differ for each image. I then created a 4 pixel long image of each color and took the average color of THAT to see if it gave me a satisfying values for each channel to adjust but the results are not good. The pages' whites are still a bit gray and dingy and the colors don't match the actual book pages.
I guess I have a lot to learn about color. I'm not looking for anything near perfection, just some adjustment I can make automatically to every single page image to make them close to real life. Any ideas?