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HISTOGRAM AND CHROMINANCE PROCESSING

  • US 20090244386A1
  • Filed: 03/27/2008
  • Published: 10/01/2009
  • Est. Priority Date: 03/27/2008
  • Status: Active Grant
First Claim
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1. A method for improving the perceived visual quality of images for instance displayed on a colour television screen, the method comprising:

  • provision of an input video signal (Y′

    , U, V) (6);

    carrying out a histogram processing (13) on said incoming video signal (6), whereby a luminance transfer function T(k) is obtained and based on said luminance transfer function T(k) calculating a global chrominance gain gc (16);

    for individual pixels of the image carrying out a chrominance processing (14) that associates a local gain g(Up,Vp) for each individual pixel having the colour components (Up, Vp);

    provision of an output video signal (Y′

    , U, V)OUT2 (18) for individual pixels wherein;

    the luminance component Y′

    OUT2 is determined by said luminance transfer function T(k);

    the first chrominance component UOUT2 is given by the expression;


    UOUT2=gcg(Up,Vp)Up; and

    the second chrominance component VOUT2 is given by the expression;


    VOUT2=gcg(Up,Vp)Vp;

    whereby the chrominance components of the individual pixels of the image are modified by a global gain factor gc relating to the characteristics of the entire image and a local gain factor g relating to the individual pixels.

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