Simple Shadow Removal

Given the location of shadows, how can we obtain highquality shadow-free images? Several methods have been proposed so far, but they either introduce artifacts or can be difficult to implement. We propose here a simple method that results in virtually error and shadow-free images in a very short time. Our approach is based on the insight that shadow regions differ from their shadow-free counterparts by a single scaling factor. We derive a robust method to obtain that factor. We show that for complex scenes - containing many disjointed shadow regions- our new method is faster and more robust than others previously published. The method delivers good performance on a variety of outdoor images.