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EP0531041A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Adaptive DCT/DPCM video signal coding method

Assignee: Panasonic Holdings Corp
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Filing: 1992-08-26
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Granted: —
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Expires: 2012-08-26
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Abstract

Abstract An input frame of video sequence is partitioned into smaller blocks of pixel data where each block is subjected to an edge detection which examines the activities in the block itself and the surrounding blocks to determine whether the block can be classified as an edge block. If the block is classified as a non-edge block, the conventional DCT coding method (eg. SM3) with or without motion compensation is applied to the block. On the other hand, if the block is classified as an edge block, the block is subjected to a pixel value prediction process with or without reference to the previously coded frames, followed by a quantization process, and a run-length encoding process with variable length codes, i.e., a DPCM process.

Inventors

  • 👤 Lucas Yau Wai Hui

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-03 11:38
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/10; H04N19/134; H04N19/136; H04N19/14; H04N19/85; H04N19/86; H04N19/102; H04N19/12; H04N19/50; H04N19/503; H04N19/51; H04N19/527; H04N19/593; H04N19/60; H04N19/61; H04N19/30

Claims Analysis

Total Claims: 3
Claim 1
Independent Claim 142 words
A video signal coding method comprising of the steps of: partitioning each frame of an input video signal into smaller blocks of pixel data; subjecting each block to an edge detection which examines the block and its surround blocks to determine if the block can be classified as an edge block; subjecting the block to a discrete cosine transform coding process, if the block is not classified as an edge block, where the block is discrete cosine transformed into DCT coefficients, quantized. zig-zag scanned, and run-length encoded with variable length codes; and subjecting the edge block to a differential pulse code modulation process, if the block is classified as an edge block, where each of the pixel value in the block is predicted, the differences between the pixel values and the predicted values are quantized and run-length encoded with variable length codes.
Claim 2
Dependent Claim 42 words
A video signal coding method according to claim 1, wherein before subjecting the said block to said discrete cosine transform coding process or said differential pulse code modulation process, said block is subjected to a motion compensation process to reduce temporal redundancy.
Claim 3
Dependent Claim 127 words
A video signal decoding method for decoding a video signal coded by a coding method according to claim 1, comprising the step of: decoding variable length encoded run-length codes to reconstruct quantized coefficients of each block of coded frames; subjecting each decoded quantized coefficient block, if it is coded by a discrete cosine transform coding process, to an inverse quantization process, and an inverse discrete cosine transformation process to reconstruct block pixel values to be placed into a frame buffer; and subjecting each coefficient in the quantized coefficient block, if the decoded quantized coefficient block is coded by a differential pulse code modulation process, to an inverse quantization and addition with a predicted pixel value to reconstruct block pixel values to be placed into the frame buffer.

References Cited (Backward Citations)

EP0434429A2 Cited

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