Detecting and Removing Shadows

Hello! I need to implement an algorithm to detect and remove shadows from images. The images aren't too important, I probably need 10 - 20 if that's not too much. I can send you some images if you agree and also I have a paper which has the algorithm to implement, unless you know a better one. My project is flexible so the algorithm isn't too important, whatever you feel comfortable with. Ideally it would be done in C but gain not vital. Anything else let me know. Thanks a lot!