Image Coding Apparatus Switching Intra Prediction Modes
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Solution Overview
Problem
The compression efficiency of lossless coding in HEVC is not sufficiently high due to its compatibility with lossy coding, which prioritizes block-by-block intra prediction, whereas DPCM coding on a pixel-by-pixel basis offers higher compression efficiency as seen in H.264.
Innovation Solution
An image coding apparatus and method that switches between lossless coding processes by using either block-by-block or pixel-by-pixel intra prediction modes, allowing for reversible and irreversible compression coding units to prioritize compatibility or compression performance based on application requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If block-by-block intra prediction is used in lossless coding to maintain compatibility with lossy coding, then compatibility is improved, but compression efficiency deteriorates
Solution Approach 1:
The patent applies dynamics by making the intra prediction method switchable between block-by-block and pixel-by-pixel bases. The coding apparatus can dynamically select which prediction method to use depending on the coding mode, allowing adaptation to different requirements while maintaining both compatibility and compression efficiency options
2Productivity
If pixel-by-pixel DPCM coding is used in lossless coding to improve compression efficiency, then compression efficiency is improved, but compatibility with lossy coding deteriorates
Solution Approach 1:
The patent enables dynamic selection between pixel-by-pixel DPCM coding and block-by-block intra prediction. When lossless coding with high compression efficiency is required, the system switches to pixel-by-pixel DPCM; when compatibility with lossy coding is prioritized, it uses block-by-block prediction, thus resolving the contradiction through conditional switching
3Productivity
If reversible compression coding with pixel-by-pixel intra prediction is used, then compression performance is improved, but device complexity increases due to multiple coding units
Solution Approach 1:
The patent applies universality by designing the second coding unit to handle multiple functions: it can perform both block-by-block intra prediction and pixel-by-pixel intra prediction depending on the mode. This multi-functionality reduces the need for completely separate coding paths, thereby managing device complexity while maintaining compression performance improvements
Data Source
AI summary
The present invention is made to enable switching between lossless coding which prioritizes compatibility with a lossy coding process and lossless coding which prioritizes compression performance.An image coding apparatus of the present invention includes the following configuration. The image coding apparatus which encodes an image on a block-by-block basis includes a first coding unit and a second coding unit. The first coding unit performs irreversible compression coding on a received first block. The second coding unit performs reversible compression coding on a received second block. The second coding unit encodes the second block by using either of a first intra prediction mode for performing intra prediction on a block-by-block basis and a second intra prediction mode for performing intra prediction on a pixel-by-pixel basis.