Transform Coefficient Continuity Smoothing for Video Block Artefact Reduction
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Solution Overview
Problem
Existing image and video compression schemes suffer from block artefacts across block boundaries during decoding, which degrade the accuracy and quality of the reconstructed frames due to quantization and transform coefficient discontinuities.
Innovation Solution
The method employs transform coefficient continuity smoothing, defined correlation coefficient smoothing, pixel range projection, and luminance correlated chrominance resampling to adjust and smooth transform coefficients, ensuring seamless transitions across block boundaries and improving decoding quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If block-based compression is used to reduce data transmission, then bandwidth efficiency is improved, but block artefacts appear across block boundaries degrading image quality
Solution Approach 1:
The patent introduces an intermediary filtering process between decoding and output. A block artefact filter is applied to the decoded image data to reduce block artefacts while preserving the benefits of block-based compression. This intermediary step mediates between the compressed representation and the final output, eliminating the harmful discontinuities at block boundaries.
Solution Approach 2:
The patent converts the harmful block artefacts into beneficial smooth transitions by applying filtering operations. The filter exploits the statistical properties of natural images to distinguish between actual image content and artefact patterns, transforming the discontinuities caused by block-based compression into seamless transitions that improve perceived quality.
2Productivity
If transform coefficient quantization is applied to compress video data, then compression ratio is improved, but transform coefficient discontinuities create block artefacts
Solution Approach 1:
The patent changes the parameters of transform coefficients through filtering operations. By modifying the transform coefficient values based on neighboring block information, the filter reduces the discontinuities introduced by quantization while maintaining the compressed representation. This parameter adjustment allows the system to achieve both high compression ratios and improved decoding accuracy.
Data Source
AI summary
Video decoding may include transform coefficient continuity smoothing, which may include coefficient continuity smoothing, defined correlation coefficient smoothing, pixel range projection, and luminance correlated chrominance resampling. Coefficient continuity smoothing may include obtaining encoded block data from the encoded bitstream, the encoded block data corresponding to a current block from the reconstructed frame, and generating reconstructed block data for the current block based on the encoded block data using transform coefficient continuity smoothing. Transform coefficient continuity smoothing may include, for a block boundary of the current block, in response to a determination that adjacent block data corresponding to an adjacent block spatially adjacent to the current block along the block boundary is available, performing transform coefficient continuity smoothing based on the current block, the adjacent block, and the block boundary, and including the reconstructed block data in the reconstructed frame, and outputting the reconstructed frame.