APPARATUS FOR DETECTING VARIATIONS IN A SUBJECT FROM A TELEVISION IMAGE THEREOF

摘要

1306975 Photo-electric monitor TOTSU K K 16 July 1970 34552/70 Heading G1A [Also in Division G4] Photo-electric monitoring apparatus includes a television system monitoring an area in which a machine is operating or a human being might enter and at least two photo-detector devices applied to different points on the T.V. screen. One detector device is applied at a reference position at which there are substantially no changes in light intensity. The other is positioned at an inspection point. The detectors, which may be CdS photo-resistors are connected in a balanced bridge arrangement 12 and may unbalance representative of change in intensity of the suspection point is amplified by differential amplifier 13 to operate relay 15, alarm 16 and lamp 17 and, if appropriate, shut down of a machine being monitored. Each detector comprises a sucker 9, a lens 7, aperture 8 and detector 6.