Photoelectric stereoplotter using a single light source

Claim 1

A STEREO PERCEPTION SYSTEM COMPRISING LIGHT MEANS TO CAUSE A SPOT OF LIGHT TO MOVE IN A PREDETERMINED PATTERN, LENS MEANS TO COLLIMATE THE RAYS OF SAID SPOT OF LIGHT, HOLDING MEANS TO HOLD A PAR OF STEROPHOTOGRAPHIC TRANSPARENCIES SO THAT THE COLLIMATED LIGHT RAYS ARE FIRST MODIFIED BY ONE STEROPHOTOGRAPHIC TRANSPARENCY AND THEN MODIFIED FURTHER BY THE SECOND STEROPHOTOGRAPHIC TRANSPARENCY SO AS TO FORM A CORRELATION PEAK WHEN THE COLLIMATED RAYS PASS THROUGH IDENTICAL PORTIONS OF SAID TRANSPARENCIES, DETECTING MEANS TO DETECT SAID CORRELATION PEAK, INDICATING MEANS TO INDICATE AT WHAT POSITION OF SAID MOVING SPOT OF LIGHT SAID CORRELATION PEAK OCCURS, POSITIONING MEANS TO MOVE SAID STEREOPHOTOGRAPHIC TRANSPARENCIES RELATIVE TO SAID LIGHT MEANS AND SAID DETECTING MEANS TO KEEP SAID CORRELATION PEAK AT A PREDETERMINED POSITION ON SAID DETECTING MEANS, SAID DETECTING MEANS COMPRISING, A PHOTOMULTIPLIER TUBE, A PEAK DETECTOR FOR DETECTING AND HOLDING THE MAXIMUM PEAK IN A PREDETERMINED TIME PERIOD, A MEANS SQUARED DETECTOR FOR SQUARING THE OUTPUT OF SAID PHOTOMULTIPLIER TUBE, A SIGNAL TO NOISE DETECTOR WHICH COMPARES THE OUTPUTS OF PEAK DETECTOR AND THE MEAN SQUARED DETECTOR AND EMITS A SIGNAL ONLY WHEN THE RATIO IS GREATER THAN A PREDETERMINED MINIMUM.