Image Codec With Selective Color-Space Conversion and Adaptive Quantization
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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 rise in the amount of transmitted information, necessitating high-efficient image compression technologies.
Innovation Solution
An image encoding/decoding method and device that utilizes selective color space conversion to improve encoding/decoding efficiency, involving determining quantization parameters based on color space conversion, transforming coefficients, and resetting residual samples through clipping to enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If color space conversion is applied to all blocks, then encoding/decoding efficiency is improved, but processing complexity and time increase
Solution Approach 1:
The patent applies color space conversion selectively only to chroma blocks where it is beneficial, rather than uniformly to all blocks. The decision to apply conversion is made based on block type and characteristics, optimizing the balance between encoding efficiency and processing complexity.
Solution Approach 2:
The patent applies color space conversion partially only to chroma components and not to luma components, and only when certain conditions are met. This partial application reduces unnecessary processing while maintaining the benefits where applicable.
2Productivity
If quantization parameter is adjusted for each block, then compression efficiency is improved, but processing time increases
Solution Approach 1:
The patent dynamically adjusts quantization parameters based on block characteristics and color space conversion status. Different quantization parameters are assigned to chroma blocks versus luma blocks, and to blocks with or without color space conversion, optimizing compression efficiency for each case.
Solution Approach 2:
The patent changes quantization parameters based on whether color space conversion is applied and block type. Multiple quantization parameter sets are defined corresponding to different block categories, allowing efficient compression while managing processing time through parameter adaptation.
3Measurement precision
If transform coefficient is calculated for all blocks, then image quality is maintained, but computational load increases
Solution Approach 1:
The patent calculates transform coefficients selectively based on block type and color space conversion status. Different transform operations are applied to chroma and luma blocks according to their specific requirements, maintaining image quality where needed while reducing computational load for blocks where conversion is not applicable.
Solution Approach 2:
The patent segments the image processing into different operations for different block types. Transform coefficients are calculated separately for chroma blocks that undergo color space conversion versus luma blocks, allowing optimization of computational resources based on local image characteristics.
Data Source
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.