Shadow elimination method for moving object detection

This paper presents a new method for eliminating shadow areas accompanied with pedestrian-like moving objects in visual surveillance systems. The proposed method removes the shadow areas by the way of height information since most of the shadow areas accompanying moving objects are assumed to be on the road plane. Two cameras are set at any locations so that their common visual fields which include the surveillance area are used for this purpose. The image obtained from one of the cameras is inversely projected to the road plane and the projected image on the road plane is transformed to the view from the other camera. Shadows existing on the road plane occupy the same areas in the transformed image and in the image acquired from the other camera, whereas objects' areas with different heights from the road plane occupy different areas in these images. Therefore, shadow areas can be removed by a subtraction between these images. An experimental result on a pedestrian crossing showed the effectiveness of the proposed method.