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 regionsour new method is faster and more robust than others previously published. The method delivers good performance on a variety of out-