×

Apparatus and methods for recompression of digital images

  • US 8,908,984 B2
  • Filed: 10/05/2010
  • Issued: 12/09/2014
  • Est. Priority Date: 10/05/2009
  • Status: Active Grant
First Claim
Patent Images

1. A method of enabling an image-adaptive, perceptually-lossless and near-maximal image compression, including:

  • compressing a first image giving rise to a second image;

    implementing a measure of added artifactual edges along coding block boundaries, including;

    computing a difference image between the first and second images;

    defining a plurality of regions within said difference image, each of said plurality of regions comprising a plurality of image blocks;

    within said region, computing for each boundary between two coding blocks a respective added-blockiness score indicating an extent of added artifactual edges along the respective boundary;

    computing a region quality score for each of said plurality of regions, based on the added-blockiness scores computed for each boundary within the region, giving rise to a respective plurality of region quality scores; and

    computing an image quality score for the second image based on one or more of said plurality of region quality scores; and

    determining, based at least upon said image quality score, whether a perceptual quality criterion is met by said second image.

View all claims
  • 4 Assignments
Timeline View
Assignment View
    ×
    ×