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.

Abstract: The field observed by a video camera includes a desired target which is to be encompassed by an electronic window. The acquisition of the target is controlled initially by a light pen to position the electronic window on the target displayed on the screen of a receiver. Automatic video tracking proceeds then by measuring the mean video level in the vicinity of the target, adjusting the signal to this level and rectifying it, and then periodically measuring the difference in energy in the two successive halves of the window along the axis in question, this measurement giving the positional divergence between the center of the window and the energy center of the target. Corresponding error signals are used to move the window to keep the target centered therein.