New Algorithm for the Range Estimation by a Single Frame of a Single Camera

An algorithm, which determines the range of a vehicle on the road by a single image, is proposed. Since it uses a single camera, there is not a problem like the high cost in the stereo camera, the millimeter wave radar and the non-robust mechanical scanning in the laser radar. And it also gives the lateral position of the vehicle. So far it is difficult to get the range information from a single camera. The algorithm overcomes this drawback by introducing a new concept, “Range Window”. It uses several portions of a captured image, namely windows. Each window is corresponding to a certain pre-determined range and has the fixed physical width and height. In each window, the size and position of an object in the image is estimated through the ratio between the widths of the object and the window and a score is given to the window. The window having the best score is determined as a best window. The range corresponding to the best window becomes an estimated range. The lateral position of the object is also calculated. This algorithm was applied to more than 4,500 real road images and showed 95% detection rate for a motorcycle, sedan, minivan, truck and bus on rural, urban and city roads. The range accuracy was about +/- 1 [m]. The present maximum range is 50 [m]. This algorithm is effective for the short range application. This is expected to be applied to “Low speed follower”.