Showing papers on "Object detection published in 1972"

Beam scanning object detection system

Abstract: A detection system and method of operation for detecting the presence of an object in a predetermined zone. The detection system includes a pulsating light-emitting device, a lens apparatus for directing the pulses of light into a beam, and a scanning device for sweeping the pulsating beam of light across the detection zone. The detection system also includes at least two photocells, one of which is positioned to receive pulses of light directly from the light-emitting device and the other is positioned to receive light after being transmitted across the detection area. The signals developed by the photocells take the form of trains of electrical signals and are correlated with appropriate electronic circuitry for detecting the absence of pulses in one of the trains of signals during the presence of pulses in the other train of signals to thereby provide an indication of the presence of an object in the detection area. The electronic circuitry also digitally processes the received signals for developing an output indication representative of the size of the object, as well as the position of the object in the detection area.