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Television camera video level control system

  • US 4,495,520 A
  • Filed: 04/09/1982
  • Issued: 01/22/1985
  • Est. Priority Date: 04/09/1982
  • Status: Expired due to Fees
First Claim
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1. A video level control system for providing a normalized video signal representing a scene including:

  • first means for providing light images of a scene and controlling the intensity of admitted light from the scene;

    second means including a camera tube responsive to the light images provided by the first means for converting the light images of a scene into electrical signals, and for conditioning the electrical signals;

    third means responsive to the electrical signals provided by the second means for providing a normalized video signal by altering the electrical signals of the second means through automatic gain control as a function of the signal remaining after clipping a pre-selected area percentage of the scene that exceeds a pre-set reference when scene luminance is in a first illumination range; and

    fourth means for controlling the first and second means so that a normalized video signal is provided when scene luminance is above the first illumination range.

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