Detecting and Removing Shadows

This paper describes a method for the detection and removal of shadows in RGB images. The shadows are with hard borders. The proposed method begins with a segmentation of the color image. It is then decided if a segment is a shadow by examination of its neighboring segments. We use the method introduced in Finlayson et. al. [1] to remove the shadows by zeroing the shadow’s borders in an edge representation of the image, and then re-integrating the edge using the method introduced by Weiss [2]. This is done for all of the color channels thus leaving a shadow-free color image. Unlike previous methods, the present method requires neither a calibrated camera nor multiple images. This method is complementary of current illumination correction algorithms. Examination of a number of examples indicates that this method yields a significant improvement over previous methods.