Chroma Subsampling with Edge Attribute Planes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Subsampling in image compression, particularly in JPEG, leads to color bleeding at image edges with low and high density values, resulting in low image quality and inadequate post-processing performance, such as smoothing, at these edges.
Innovation Solution
An image compressing/decompressing apparatus that includes a subsampling unit for chroma planes at a predetermined resolution, a compression processing unit for the luma and subsampled chroma planes, a decompression processing unit, and an interpolation processing unit that restores the chroma planes to their original resolution based on an attribute plane indicating edge existence, allowing for effective compression and post-processing like smoothing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If subsampling is performed on chroma planes to achieve compression, then compression ratio is improved, but color bleeding occurs at image edges and image quality deteriorates
Solution Approach 1:
The patent applies different subsampling strategies to different regions of the image based on edge detection. Areas with edges (detected through attribute planes) receive different handling compared to smooth regions, allowing the system to maintain compression benefits while preventing color bleeding at critical edge locations
Solution Approach 2:
The patent performs edge detection and attribute plane generation before subsampling the chroma planes. This preliminary action allows the system to identify regions that require special attention during compression, enabling selective subsampling that avoids color bleeding while maintaining overall compression efficiency
2Productivity
If subsampling is performed on chroma planes to reduce data size, then compression efficiency is improved, but post-processing such as smoothing cannot be properly performed at edge parts
Solution Approach 1:
The patent performs edge detection and creates attribute planes before compression and subsampling. This preliminary action preserves edge information that can be used during post-processing operations, ensuring that smoothing and other operations can be properly applied to edge regions even after compression
Solution Approach 2:
The patent introduces attribute planes as intermediary structures that carry edge information separately from the chroma planes. These attribute planes act as mediators that preserve edge details through compression while allowing post-processing operations to access and work with this edge information accurately
Data Source
AI summary
A subsampling unit (2) converts pixel values of plural pixels in a pixel block in the chroma plane to one pixel value associated with the pixel block on the basis of values in the pixel block in an attribute plane that indicates existency of an edge at the predetermined resolution. A compression processing unit (3) performs a compression process for a luma plane and the chroma planes for which the subsampling has been performed by the subsampling unit (2).