Image Processing Apparatus Chrominance Adjustment for Cross-Color Reduction

The patent segments the chrominance adjustment process into multiple stages: first calculating edge luminance parameters to identify high-frequency luminance regions, then calculating edge chrominance parameters to detect cross-color areas, and finally applying selective chrominance adjustment only in identified cross-color regions. This segmentation allows the system to distinguish between genuine chrominance signals and false chrominance caused by high-frequency luminance, thereby eliminating cross-color while preserving accurate chrominance elsewhere.

The patent applies local quality by adjusting chrominance parameters selectively in different image regions. Specifically, it calculates a chrominance adjustment value based on edge chrominance parameters only in regions where cross-color is detected, while leaving other regions unchanged. This localized adjustment ensures that cross-color is corrected without affecting the overall image quality or introducing artifacts in non-cross-color areas.

The patent transitions from a static frame-averaging approach to a dynamic approach that adapts to motion. It introduces motion detection by comparing current frame with previous frame, calculates motion vectors to identify moving objects, and then applies chrominance adjustment selectively based on both motion information and edge chrominance parameters. This dynamic adaptation allows the system to maintain chrominance accuracy for moving objects while still correcting cross-color effects.

The patent implements feedback mechanisms by using calculated edge chrominance parameters and motion information to continuously adjust chrominance values. The system calculates chrominance adjustment values based on feedback from edge detection and motion analysis, then applies these adjustments and continues monitoring for further corrections. This closed-loop feedback ensures that chrominance accuracy is maintained dynamically as objects move through the scene.

The patent applies local quality by restricting chrominance adjustment to specific regions where cross-color is detected through edge chrominance parameter calculation. The system determines a chrominance adjustment value and applies it only in regions identified as having cross-color, while leaving saturation and brightness in other regions unchanged. This selective regional adjustment eliminates cross-color without introducing saturation or over-brightness artifacts in non-cross-color areas.

The patent introduces edge chrominance parameters as an intermediary mechanism to mediate between cross-color correction and saturation preservation. The edge chrominance parameters serve as a diagnostic tool to identify where adjustment is needed, acting as a gatekeeper that prevents unnecessary chrominance modification in regions where it would cause saturation or over-brightness. This intermediary approach ensures adjustments are made only where beneficial.