Method for detecting and separating the shadow of moving objects in a sequence of digital images

摘要

For detecting and separating the shadow of moving objects in a sequence of digital images, a sequence of background images is first determined from a sequence of images, this sequence of background images containing only the non-moving image background of the sequence of images but not the moving objects. Object edges are then extracted from the sequence of images in that in each case an edge gray-value image is determined for each image of the sequence of images and for each respective corresponding background image of the sequence of background images. Using vertical or horizontal projection of these edge gray-value images, corresponding vertical or horizontal edge histograms are determined in each case for the edge gray-value images. Edges which do not belong to moving objects or shadows of moving objects are eliminated, in that the edge histograms of a background image are subtracted from the corresponding edge histograms of the image, belonging to the same instant, of the sequence of images and in that the differential edge histograms formed in this manner are subjected to a threshold value discrimination, by which means those edges are eliminated which do not correspond to the actual moving objects but rather to a shadow of a moving object.