For my final year project i'l be taking the photographs from the mobile phone and then will be computing the image processing steps. I will the taking the images under various illumination conditions (natural light, poor lightning conditions and so on). Does any one knows any algorithm that I can use to compute it?
Thanks a lot
One very simple method is to take the mean pixel value of an image, adjust the exposure, take another picture and compute the mean again, continuing until the mean reaches some arbitrary value.
Good whitebalancing is still an active field of research I guess. From your question, it is hard to tell how "advanced" the sought solution is supposed to be and what you need exactly.
In some other context, I recently encountered this paper. They have a quite complicated approach for Whitebalancing and produce good results:
Hsu, Mertens, Paris, Avidan, Durand. "Light mixture estimation for spatially varying white balance". In: ACM Transactions on Graphics, 2008
Check the related work section for more hints, as usual.
If you are less interested in whitebalancing but rather require to process the images further (sounds a bit like that in your comment), you should possibly aim for techniques that are rather invariant to illumination - or at least robust against changes in illumination. E.g. transforming your image in any colorspace that separates the brightness/luminance (i.e. YUV, HSV) might help, depending on your actual problem. From my experience and intuition, I would suggest that in most cases it is better to make your "recognition"-algorithm robust agains changes in illumination - rather than correcting the illumination first.