Quick elimination of vehicle shadow by multi threshold image segmentation

Moving shadow is usually misinterpreted as part of moving object because of its similarity with the object in video target segmentation, and the processing speed of traditional shadow elimination method can not meet the requirement of real-time intelligent transportation system. A new shadow elimination method is proposed. In this method, every color image of a video is transformed into gray images; and difference image is obtained by calculating the difference between the gray image and its background; then the difference images are transformed into binary images with a positive threshold and a negative threshold. By selecting these two thresholds appropriately for both light-colored and deep-colored objects, only target object remains in the binary images. In the experiments of real-time vehicle detection, this method demonstrates a good performance of quick shadow elimination compared to traditional method. It can be applied to moving object detection, tracking and other real-time applications.