Optical tracking system

Abstract

A light-emitting target within the field of view of an optical objective is focused within a generally rectangular detection area upon a continuously moving code carrier which is subdivided into a multiplicity of juxtaposed strip zones parallel to the direction of motion, each strip zone forming a pseudo-random binary optical code pattern recurring one or more times throughout its length. The motion of the code carrier generates a pulsed light beam which is intercepted by a photoelectric transducer unit and, after electric amplification, is reconverted by a photoemissive unit into a train of luminous pulsations projected onto the code carrier in a correlation area traversed at every instant by a code pattern identical with that of the detection area. The light gated by the matching code of the correlation area is focused upon the screeen of a camera tube which therefore receives a bright spot at a point whose location on the screen corresponds to that of the target image on the detection area. The transducer unit may comprise a set of linear detectors, aligned with respective strip zones, in which case the photoemissive unit has a like number of linear light emitters parallel to the direction of carrier motion. With a single detector receiving light from the entire detection area, feeding a single light emitter, the code patterns of the several strip zones are mutually distinct.