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Data compression for colour images using wavelet transform

  • US 20050169548A1
  • Filed: 04/09/2003
  • Published: 08/04/2005
  • Est. Priority Date: 04/19/2002
  • Status: Active Grant
First Claim
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1. A method of data compression for colour images wherein it incorporates the following steps:

  • a) establishing a value for a number of scales into which a wavelet transformation is to be made;

    b) distinguishing areas in an original colour image of relatively higher importance from those of relatively lower importance;

    c) transforming the colour image into a second image in a different colour system having relatively more image information in a first component and relatively less in other components;

    d) sub-sampling the other components to reduce their respective numbers of pixels;

    e) transforming the first component and the sub-sampled components into wavelet coefficients with the said number of scales;

    f) transforming the importance-distinguished areas to correspond to location and number of scales of the wavelet transformation; and

    g) establishing a wavelet coefficient threshold and forming a reduced wavelet image by discarding wavelet coefficients which both correspond to image areas of relatively lower importance and are below the said threshold.

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