Image Compression Tile Boundary Artefact Elimination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
JPEG2000 compression introduces tile boundary artefacts at high compression rates, reducing image quality when lossy compression is used, making it difficult to reduce the size of compressed image data effectively.
Innovation Solution
Process images by blanking out most of the unchanged areas near their boundaries before compression, ensuring that original image content remains adjacent to changed areas, thereby eliminating tile boundary artefacts and allowing for efficient compression without quality degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If lossy compression is used to reduce file size, then compression efficiency is improved, but tile boundary artefacts appear reducing image quality
Solution Approach 1:
The patent applies preliminary action by pre-processing the image data before compression - specifically, it identifies unchanged areas and preserves their original content near tile boundaries while compressing other areas. This preparatory step ensures that when compression is applied, the boundary regions maintain their original quality, preventing artefact formation during the compression process.
Solution Approach 2:
The patent implements local quality by applying different processing strategies to different regions of the image. Unchanged areas near tile boundaries are preserved with original quality, while other areas undergo full compression. This localized approach ensures high quality at critical boundary regions while maintaining overall compression efficiency.
2Productivity
If unchanged areas are completely blanked out to reduce data size, then compression efficiency is improved, but tile boundary artefacts appear at area boundaries
Solution Approach 1:
Instead of uniformly blanking out unchanged areas, the patent applies local quality by preserving original image content in specific sub-regions near tile boundaries while blanking out other portions of unchanged areas. This selective preservation eliminates boundary artefacts while still achieving significant compression on the blanked portions.
Solution Approach 2:
The patent segments unchanged areas into different zones: regions near tile boundaries that are preserved to prevent artefacts, and interior regions that can be blanked out for compression. This segmentation allows differential treatment of sub-regions within unchanged areas.
Data Source
AI summary
A method for processing graphical data representing a sequence of images prior to compression, including analyzing a plurality of adjacent areas of an image from the sequence to determine: (i) a first set of areas, each of which includes changes when compared with a corresponding area in a previous image from the sequence; and (ii) a second set of areas, each of which does not include a change when compared with a corresponding area in the previous image. For each area of the second set, a section of the area is replaced with a block chosen to reduce the size of the graphical data once compressed, while leaving the original image of the area of the second set adjacent any part of the perimeter that adjoins an area of the first set. A dataset is provided to allow identification of the areas of the second set. On decompression of the compressed graphical data, the dataset is accessed and the image is processed by replacing each area of the second set with the corresponding area from a previous image. A system for processing the graphical data according to the steps set out above is also provided.