Block Effect Reduction in Image Processing Using Pixel Difference Thresholds
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Solution Overview
Problem
Existing image processing technologies face challenges in effectively removing block effects from images, especially when compression/decompression information is unavailable, due to the variety of image media used.
Innovation Solution
An image processing method and device that detects edges in an image, determines if they are block effects by calculating pixel differences, and filters them out using an edge detector, block effect detector, and block effect filter, without requiring compression/decompression information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If DCT compression is performed on images, then image compression efficiency is improved, but block effects appear on block boundaries
Solution Approach 1:
The patent changes the parameter of pixel difference threshold to distinguish block effects from real edges. By setting a predetermined range for pixel differences, the method identifies block effects (which have small pixel differences across boundaries) and filters them selectively, resolving the contradiction between maintaining compression efficiency and eliminating block artifacts.
2Measurement precision
If compression/decompression information is used to remove block effects, then block effect removal accuracy is improved, but device complexity increases due to need for information from multiple sources
Solution Approach 1:
The patent applies self-service by using only the image data itself for block effect detection and removal. The method calculates pixel differences directly from the decoded image pixels without requiring external compression/decompression information, making the system self-sufficient and reducing complexity while maintaining effective block effect removal.
Solution Approach 2:
The patent introduces an intermediary mechanism - a predetermined pixel difference range - that mediates between the need for accurate block effect detection and the availability of only basic image data. This intermediary threshold system enables accurate detection using simple pixel comparison, bridging the gap between detection accuracy requirements and limited information availability.
3Productivity
If pixel difference thresholding is applied to detect block effects, then block effect filtering effectiveness is improved, but risk of misidentifying real edges increases
Solution Approach 1:
The patent applies local quality by considering the local context around edges when determining whether to filter them. The method examines pixel differences in specific locations relative to detected edges and applies filtering only where the pixel difference falls within the predetermined range, preserving real edges with significant pixel differences while removing block effects with minimal differences.
Data Source
AI summary
The present invention provides an image processing method for processing an image. The method includes: detecting at least an edge in the image; selecting at least a first pixel and at least a second pixel according to the edge; deciding whether the edge is a block effect by determining whether a pixel difference between the first pixel and the second pixel locates in a predetermined range; and filtering out the detected block effect.