Relative velocity detector for vehicles travelling in other lanes.

This paper describes a system that uses a video camera mounted on the roof of a moving car to measure the relative velocity of a vehicle traveling in another lane of the same highway. The algorithm can determine the relative velocity every 66 ms. Whether or not a moving vehicle exists in the camera image is determined by differentiating images in several small windows into successive fields. Each window independently outputs the relative velocity of a part of the moving vehicle. Thus, the relative velocity of the entire moving vehicle can be determined by clustering the outputs of multiple independent windows. (A)