Patent ID: 8331664
Filing Date: 2012-12-11
Classification: G06T,H04N

Abstract:
1. A method of compressing a block of multiple pixels into a compressed block representation, each pixel comprising a respective color having multiple color components, said method comprising the steps of: providing, for at least one pixel of said block, a first prediction of a first color component of said at least one pixel by: a) calculating said first prediction based on a first weighted combination of a first color component of a first neighboring pixel in said block and a first color component of a second neighboring pixel in said block employing non-zero weights if a magnitude difference between said first color components of said neighboring pixels is smaller than a threshold; b) selecting said first prediction to be based on one of a second different weighted combination of said first color components of said neighboring pixels and a third different, weighted combination of said first color components of said neighboring pixels if said magnitude difference is not smaller than said threshold; and c) providing a guiding bit associated with said selected one of said second weighted combination and said third weighted combination if said magnitude difference is not smaller than said threshold; and calculating, for each pixel in said block, a difference between a respective second color component of said pixels and said respective first color component of said pixels; providing a second prediction of a second color component of said at least one pixel by: a′) calculating said second prediction based on a first weighted combination of a first difference between a second and said first color component of said first neighboring pixel and a second difference between a second and said first color component of said second neighboring pixel if said magnitude difference is smaller than said threshold; b′) selecting, if said magnitude difference is not smaller than said threshold, said second prediction to be based on one of a second different, weighted combination of said first difference and said second difference and a third different weighted combination of said first difference and said second difference based on said guiding bit; calculating a first prediction error based on said first color component of said at least one pixel and said first prediction; calculating a second prediction error based on a difference between said second and first color component of said at least one pixel and said second prediction; determining a first encoded representation of said first prediction error; and determining a second encoded representation of said second prediction error, wherein said compressed block representation comprises said first encoded representation, said second encoded representation and said optional guiding bit.