Optoelectronic system for passive range metering

Claim 1

Optoelectronic system for passive metering of the distance of a vehicle moving approximately rectangular with respect to the line of sight of said system, comprising (a) an optical receiver directed to the traveling path of the vehicle at an angle of 90°-φ and having two detectors spaced apart in its focal plane and further having lens means provided in front of said detectors; (b) time measuring means for measuring on the one hand the time (t i ) which the image of the vehicle needs for traveling through one of the detectors and on the other hand for measuring the time (t ik ) which the image of a vertical edge of the vehicle needs for traveling from the first detector to the second detector; (c) calculating means for generating an electrical signal (Q t ) corresponding to the quotient (t ik /t i ) of said two time signals and further for generating a distance signal ##EQU10## for the distance E between the optical receiver and a section point of the vehicle traveling path with a line extending perpendicular to said path and going through the receiver, wherein f is the focal distance of the lens means, l is the length of the vehicle, d ik is the distance between the two detectors, φ is the angle between a line E' extending from the receiver to the image of the second detector as projected by said lens means on said path and a line E from the receiver to said section point.