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TELEVISION SURVEILLANCE SYSTEM

  • US 3,781,468 A
  • Filed: 06/21/1972
  • Issued: 12/25/1973
  • Est. Priority Date: 06/21/1972
  • Status: Expired due to Term
First Claim
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1. A surveillance system including a closed circuit television arrangement having a camera viewing a scene which includes the area to be protected and having a monitor for displaying an image of the scene viewed by said camera, said system including means for separating the horizontal and vertical synchronizing signals from the video signals generated by said camera, first means responsive to said synchronizing signals for generating a window signal indicative of that portion of the time during each field that a preselected rectangular fraction thereof is being scanned, and second means responsive to said synchronizing signals for generating timing waveforms, characterized in that said second means comprises a binary counter operated by said vertical synchronizing signals for generating repeatedly a series of successive binary number signals from zero to its capacity and also comprises a decoder operated by said binary number signals for generating a plurality of repetitivE series of voltage pulses on a like plurality of output conductors, each of said series having a duration approximately equal to the duration of an integral multiple of fields, and in that said system includes a peak detector for detecting and storing the peak magnitude of a video signal applied thereto, means controlled by said timing waveforms and said window signal for applying that portion of the video signal occurring during the time defined by said window signal and one of said series of pulses to said peak detector, means for generating a reference signal, means enabled by one of said waveforms for comparing the magnitudes of the signal stored by said peak detector and said reference signal, and means responsive to a difference in said magnitudes in excess of a predetermined threshold for generating a warning signal.

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