Extracting mobile objects by sequential background detection on a video

This paper describes a technique for extracting moving objects from a video image sequence taken by a slowly moving camera as well as a fixed camera. The background subtraction method is effective for extracting moving objects from a video. But the latest background image should be employed for the subtraction in the mobile camera case and in order not to be influenced by the light intensity change. A temporal median technique is proposed in this paper which detects the background at every moment. The camera motion is estimated using a local correlation map and the temporal median filter is applied to the common image area among a set of successive image frames to extract the background. The technique was applied to the video images obtained at a junction from a hand-held camera and those taken at a pedestrians crossing by a camera fixed in a car and successfully detected pedestrians. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008