Video Signal Processor Noise Reduction Memory Optimization
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Solution Overview
Problem
Existing video signal processing methods fail to accurately remove cross-color noise from NTSC and PAL video signals without causing color smear, especially when luminance motion is not detectable, and require excessive memory for effective noise reduction.
Innovation Solution
A video signal processor that uses frame recursive luminance and color difference noise reduction techniques, allowing for accurate detection of color motion without requiring more than one frame of luminance data and two frames of color difference data, thereby avoiding color smear and reducing random noise effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the averaging process is applied to remove cross-color noise, then cross-color noise is reduced, but color smear occurs when color motion is present
Solution Approach 1:
The patent applies preliminary anti-action by detecting color motion before applying the averaging process. The motion detection unit examines color difference signals to determine whether color motion is present, and only applies averaging when no color motion is detected, thereby preventing color smear while maintaining cross-color noise removal effectiveness
Solution Approach 2:
The patent implements dynamics by making the averaging process conditional rather than static. The processing mode switches between averaging and non-averaging based on real-time motion detection results, allowing the system to adapt its noise removal strategy to the current frame's motion characteristics
2Device complexity
If luminance motion detection is used to control averaging, then processing is simplified, but color motion cannot be detected when luminance signal remains unchanged
Solution Approach 1:
The patent introduces color difference signals as an intermediary for motion detection. Instead of relying solely on luminance signals, the system uses color difference signals to detect color motion, providing an additional detection channel that works effectively even when luminance remains unchanged
Solution Approach 2:
The motion detection unit serves multiple functions: it detects both luminance motion (for overall motion control) and color motion (for cross-color noise removal control). This multi-functional approach allows the system to handle various motion scenarios comprehensively
3Measurement precision
If two-frame luminance signal memory is required for PAL format, then color motion detection accuracy is improved, but memory requirements increase
Solution Approach 1:
The patent merges the storage of luminance and color difference signals into a unified memory structure. By combining these memory requirements, the system achieves the necessary two-frame retention for PAL format while optimizing overall memory utilization and avoiding separate dedicated memory allocations
Data Source
AI summary
A video signal processor recursively removes noise from luminance signal data, storing only one frame of the luminance signal data, and detects luminance motion by comparing the current and stored luminance data to decide whether to output the current color difference data, the average of the current color difference data and the color difference data one frame before, or the average of the current color difference data and the color difference data two frames before. The decision may also involve detection of color noise by comparison of the color difference data with the data one frame before, or detection of color motion by comparison of the color difference data with data two or four frames before. Color data stored for color noise detection may also be used for recursive color noise removal. Accurate noise reduction is possible with a comparatively small amount of memory.