Is there a good example for doing white balance on ...

Hi, Is there a good Matlab code example that can run a white balance algorithm on a variety of well color distributed images under different color temperatures?

Thanks.

Answer 1

[Image Analyst]

Well I have some. But it's about 500 lines of code so I'm not going to post it here. It also works off the x-rite color checker chart, which you can see in my File Exchange that has been snapped by a camera. It depends on how accurate you want to be. I'm sure you can find some simple but inaccurate methods that just subtract some offset from the different color channels, or, better, apply a multiplicative factor to each channel. But a more accurate way is to image a known standard, such as the x-rite color checker chart, measure each of the chip colors, and then develop a transform to map the bad RGB image into the desired RGB image (which you can assume are the sRGB values supplied by x-rite). I know Grant on the image processing team at the Mathworks has a demo for that since he showed it to me last week. He said he has it on an FTP site somewhere - ask him. There are even more accurate methods that involve correcting for the shading in the camera and the OECF of the camera but I don't want to get into those.