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Optimal tone scale mapping in electronic cameras

  • US 5,539,459 A
  • Filed: 05/18/1995
  • Issued: 07/23/1996
  • Est. Priority Date: 05/18/1995
  • Status: Expired due to Term
First Claim
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1. An electronic still camera comprisingmeans for defining an image plane;

  • optical means for directing image bearing light from a scene to said image plane to form an optical image of the scene on the image plane;

    photosensitive means located at said image plane for receiving said image bearing light and producing therefrom analog image signals representative of pixels of said image wherein voltage magnitudes of the analog image signals are indicative of pixel intensity;

    video signal processing means for transforming the analog image signals according to a gamma curve so as to adjust a tone scale of the image such that sharp changes in tone are elongated and relatively flat changes in tone are compressed thus creating a transformed signal;

    analog-to-digital conversion means for converting said transformed signal to a stream of digital image signals representative of the image; and

    processing means for selectively processing, storing or transmitting image data represented by the digital image signals.

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