Run length coding with context model for image compression using sparse dictionaries
AssigneeSony Corporation
InventorsThai-Ha Nguyen, Ali Tabatabai
Life of this patent
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Abstract
Apparatus and methods for coding images geometric vector quantization (GVQ) having an over-complete dictionary which produces a sparse vector of coefficients as it contains large runs of zeros. The sparse encoding is particularly well suited for use with run-length entropy coding techniques. Image blocks are sparse coded using GVQ, with the vector of coefficients converted to RUN-LENGTH symbols, and binarized into a set of binary symbols. At least a portion of the binary symbols are used as contexts which can be selected when performing binary arithmetic coding of the binary coded RUN and LENGTH data to generate a bit stream containing the encoded image that provides enhanced compression.
Claims20
An apparatus for encoding image blocks from images, comprising:
- a sparse coder configured for geometric vector quantization of an image block, having a number of pixels, from an input image in response to selecting a pattern from a finite set of geometric patterns contained in a dictionary, and generating a number of coefficients within a vector of coefficients representing said image block;
- wherein the number of coefficients within said vector of coefficients exceeds the number of pixels in the image block in response to sparse decompositions of the image block arising from utilizing said dictionary which is over-complete;
- and
- a run-length coder configured for converting said vector of coefficients to symbols which are arithmetically coded into a bit stream output.
An apparatus for encoding image blocks from received images, comprising:
- a computer configured for encoding an image;
- and
- programming executable on said computer for performing steps comprising:
- dividing the image into a plurality of image blocks, each having a number of pixels;
- performing a geometric vector quantization operation on an image block within a plurality of image blocks in response to a finite set of geometric patterns contained within a dictionary, which is over-complete, to generate a sparse coding within a vector of coefficients;
- and
- converting said vector of coefficients to symbols, which are arithmetically coded into a bit stream output in response to switching between a plurality of context models.
A method of encoding image blocks from received images within an image encoding device, comprising:
- dividing an image into image blocks;
- performing geometric vector quantization on each image block in response to an over-complete dictionary to generate a sparse coding within a vector of coefficients;
- and
- converting said vector of coefficients to symbols which are arithmetically coded into a bit stream output in response to switching between context models.
Dependencies are inferred from the claim text.