Selective Chroma Color-Space Conversion for Efficient Image Coding
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Solution Overview
Problem
The increasing demand for high-resolution and high-quality images leads to a significant increase in transmission and storage costs due to the increased amount of information, necessitating high-efficient image compression technology.
Innovation Solution
An image encoding/decoding method and device that utilizes selective color space conversion to improve encoding/decoding efficiency by determining quantization parameters and transform coefficients based on color space conversion, with clipping to predetermined limits, and includes a processor for these operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If color space conversion is applied to all blocks, then encoding efficiency is improved, but processing complexity and time increase
Solution Approach 1:
The patent applies color space conversion selectively only to chroma blocks rather than all blocks. This local quality approach optimizes encoding efficiency for chroma components while avoiding unnecessary processing for luma blocks, thereby reducing overall processing time and complexity.
Solution Approach 2:
The patent applies color space conversion partially only to chroma blocks and not to luma blocks. This partial action principle reduces the computational burden while maintaining the encoding benefits where most needed, effectively balancing efficiency improvement with processing time reduction.
2Productivity
If quantization parameter is adjusted without clipping, then compression ratio improves, but value stability and reliability deteriorate
Solution Approach 1:
The patent applies clipping to constrain the quantization parameter within a predetermined range before it is used in calculations. This beforehand cushioning prevents unstable or extreme quantization values from compromising reliability, while still allowing sufficient compression ratio through controlled parameter adjustment within the clipped range.
3Device complexity
If selective color space conversion is applied, then processing complexity is reduced, but encoding efficiency may deteriorate
Solution Approach 1:
The patent applies color space conversion selectively only to chroma blocks rather than all blocks. This local quality approach optimizes encoding efficiency for chroma components while avoiding unnecessary processing for luma blocks, thereby reducing overall processing complexity.
Solution Approach 2:
The patent applies color space conversion partially only to chroma blocks and not to luma blocks. This partial action principle reduces the computational burden while maintaining the encoding benefits where most needed, effectively balancing efficiency improvement with processing complexity reduction.
Data Source
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AI summary
Provided are an image encoding/decoding method and device. An image decoding method performed by an image decoding device according to the present disclosure includes the steps of: determining a quantization parameter of the current block on the basis of whether color space conversion is applied to a residual sample of the current block; determining a transform coefficient of the current block on the basis of the quantization parameter; determining the residual sample of the current block by using the transform coefficient; and resetting the value of the residual sample on the basis of whether the color space conversion is applied.