System and method for estimating lateral position

摘要

A system for estimating lateral offset of a vehicle from a centered position on a road is comprised of a video camera and a digitizer to produce digitized input signals representative of the road ahead of the vehicle. A circuit is provided for sampling the digitized input signal to create a perspective-free image comprised of rows and columns of pixels. The curvature of the road is determined by ascertaining an amount by which each row of pixels of the perspective-free image must be horizontally shifted to cause features to appear in the perspective-free image as a straight line. Each column of pixels of the perspective-free image is added to produce a single row, referred to as a current scanline profile, representative of the vehicle's position on the road. The current scanline profile is compared with a template profile representative of the vehicle's position when properly centered on a straight road to determine an amount by which the current scanline profile must be shifted to arrive at an optimal correlation with the template profile. The amount that the current scanline profile must be shifted is representative of the lateral offset of the vehicle from the center of the road. Circuitry is responsive to the lateral offset and the curvature of the road to produce an appropriate output signal.