Image Processing Circuit for Video Signal Distortion Reduction
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Solution Overview
Problem
MPEG decoder format conversions from '4:2:0' to '4:2:2' formats in DVD players often result in errors due to field-decoding methods, causing distortion or falsification of common boundaries in images.
Innovation Solution
An image processing circuit comprising a separator to split video signals into brightness and color components, with dedicated vertical filters for each component to reduce distortions, allowing independent filtering characteristics for brightness and color signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If field-decoding method is used for format conversion from 4:2:0 to 4:2:2, then compression rate is improved, but image quality deteriorates due to distortion and falsification of common boundaries
Solution Approach 1:
The video signal is segmented into brightness component (Y) and color components (Cb, Cr) using a separator. Different filtering operations are applied to each component independently - the brightness component undergoes vertical filtering to eliminate distortion, while color components are processed separately to maintain color accuracy. This segmentation allows targeted processing that resolves the boundary distortion problem while preserving compression efficiency.
2Adaptability or versatility
If additional color samples are generated through interpolation procedure, then format conversion is achieved, but common boundaries become distorted or falsified
Solution Approach 1:
The patent separates brightness and color sampling processes. The brightness signal is upsampled using vertical filtering that preserves edge accuracy, while color samples are generated independently. This segmentation prevents the boundary distortion that occurs when color and brightness are interpolated together, as the brightness-guided upsampling maintains accurate object boundaries.
Solution Approach 2:
The brightness component serves as an intermediary guide for the upsampling process. The vertical filter processes the brightness signal first, and its output guides the generation of additional color samples. This intermediary approach ensures that new color samples are placed at correct boundary positions, preventing falsification while achieving the required 4:2:2 format.
Data Source
AI summary
An image processing circuit for processing a video signal includes: a separator for separating the video signal into a brightness signal and a color signal; a first filter coupled to the separator for filtering the color signal; and a second filter coupled to the separator for filtering the brightness signal.