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Image sequence compression and decompression

  • US 5,841,473 A
  • Filed: 10/31/1996
  • Issued: 11/24/1998
  • Est. Priority Date: 07/26/1996
  • Status: Expired due to Fees
First Claim
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1. A method of compressing and decompressing a sequence of images, comprising the steps of:

  • compressing the sequence of images into a compressed sequence, by performing the steps of;

    digitizing each image in the sequence into an image frame comprising an array of intensity coefficients arranged in first and second directions;

    performing an intraframe decomposition of each image frame by the steps of;

    performing averaging and differencing of the image frame in a first direction to generate average and difference coefficient sequences;

    downsampling the average and difference coefficient sequences;

    performing averaging and differencing of the image frame in a second direction; and

    downsampling sequences from the step of performing averaging and differencing of the image frame in the second direction, to generate a decomposed image frame;

    performing an interframe decomposition of groups of decomposed image frames to generate a compressed sequence of image frames;

    decompressing the compressed sequence of images into a reconstructed sequence, by performing the steps of;

    performing an interframe reconstruction of the groups of decomposed image frames; and

    then performing an intraframe reconstruction of each image frame by the steps of;

    upsampling the average and difference coefficient sequences;

    performing average and difference combining of the upsampled sequences in the second direction;

    upsampling sequences resulting from the step of performing average and difference combining; and

    performing averaging and differencing of the image frame in the first direction, to generate a reconstructed image frame;

    wherein one of the intraframe decomposition and intraframe reconstruction steps further comprises;

    performing Cholesky filtering upon coefficient sequences corresponding to the image frame.

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