BDPCM Image Decoding for Higher Intra Prediction Accuracy
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Solution Overview
Problem
The increasing demand for high-resolution and high-quality images leads to higher transmission and storage costs due to the increased amount of information, necessitating a more efficient image compression technique.
Innovation Solution
An image decoding method and apparatus that utilizes Block-based Delta Pulse Code Modulation (BDPCM) to derive prediction samples, residual coefficients, and reconstructed samples, storing the intra prediction mode based on a BDPCM direction flag to improve coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional image transmission and storage methods are used for high-resolution images, then image quality is maintained, but transmission cost and storage cost increase
Solution Approach 1:
The patent extracts and transmits only the residual difference between the original image and the predicted image, rather than transmitting the entire high-resolution image. This is achieved through intra-prediction where the decoder predicts pixel values based on neighboring pixels, and only the prediction error (residual) is encoded and transmitted, significantly reducing the data volume while maintaining image quality
Solution Approach 2:
The patent changes the encoding parameter from transmitting absolute pixel values to transmitting relative residual values. By using BDPCM (Block-based Delta Pulse Code Modulation) and other prediction techniques, the image data is transformed into a form where only the difference from predicted values is stored, reducing the effective parameter space that needs to be transmitted and stored
2Productivity
If BDPCM is applied to improve coding efficiency, then residual coding efficiency improves, but device complexity increases
Solution Approach 1:
The patent applies preliminary prediction actions before residual encoding by using intra-prediction modes and BDPCM to predict pixel values based on already decoded neighboring pixels. This preliminary prediction step simplifies the subsequent residual encoding process, as the residuals become smaller and more compressible, improving overall coding efficiency while keeping the additional complexity manageable
Solution Approach 2:
The patent segments the image into blocks and applies different prediction and encoding strategies to different blocks. By dividing the image into smaller units, the complexity of BDPCM and intra-prediction is localized to individual blocks, making the overall decoding process more manageable while achieving better compression through block-level optimization
Data Source
AI summary
An image decoding method performed by a decoding apparatus according to the present document comprises the steps of: deriving prediction samples for a first sample and a second sample of the current block on the basis of BDPCM-related information about the current block and neighboring samples of the current block; deriving residual samples for the first sample and the second sample on the basis of a residual coefficient of the first sample and a modified residual coefficient of the second sample; and storing, as the intra prediction mode of the current block, the intra prediction mode in the prediction direction of the current block, which is derived on the basis of a BDPCM direction flag.