Patent US 5,680,313

A system and method detects obstacles in a road being traveled by a vehicle. Edge points of the road are calculated from known road data. A series of scan lines are made of the road ahead of the vehicle to obtain an image plane of the road ahead of the vehicle. The calculated edge points are projected into the image plane to determine the left and right edge points of each scan line in the image plane. Each scan line is processed to locate any discontinuities between the left and right edge points, where the discontinuities correspond to objects in the road.