Apparatus for and method of detecting object on road

摘要

A detector set on a motor vehicle emits a beam of light forward and receives a beam reflected from an object and determines the distance to the object. Displacement in the direction of emission of the beam is detected and corrected by recognizing the received beam as having been reflected by an overhead beam reflector of a known height of a part of the road surface and by measuring the distance to the point where the reflection has taken place. The slope of the beam-reflecting road surface may be used to determine the displacement of the direction of beam emission. The speedometer of the motor vehicle may be checked to determine whether it is running at a constant speed such that only measurements taken while the vehicle is running smoothly can be used for the calculation.