Patent US 6,493,458

An apparatus and method for correctly determining the position of a vehicle in a traffic lane by obtaining correct information about the position of the traffic lane without being affected by variations in the road surface, weather, time of day, or such imaging conditions as fixed or moving lighting, are provided. An edge signal of a high spatial frequency component and a luminance signal of a low spatial frequency component of a digital image signal representing the view of the local area to the front of a vehicle are extracted. A road contour signal is then extracted from the edge signal, and a road region signal is extracted from the luminance signal. The position of the lane Sre is then detected with high precision by evaluating the lane contour Sre based on the road region signal Srr and lane contour data Sre.