Color Gamut Mapping Device Preventing Contour Artifacts
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Solution Overview
Problem
Display devices face challenges in maintaining color accuracy due to contour and color fading phenomena during color gamut mapping, especially when transitioning between different color gamuts, such as from sRGB to wider color gamuts like those in liquid crystal or organic light-emitting diode displays.
Innovation Solution
A color gamut mapping method and device that converts input image signals into luminance and chrominance components, calculates hue angles, selects appropriate hue axes, and adjusts saturation and hue gains for precise control within divided control areas, interpolates luminance gains based on grayscale differences, and inversely converts signals to maintain color accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If color gamut mapping is performed to extend color gamut from sRGB to wider color gamut displays, then color reproduction capability is improved, but contour phenomenon and color fading occur during luminance tuning
Solution Approach 1:
The color gamut mapping process is segmented into multiple independent modules: color space conversion module, hue calculation module, hue axis selection module, parameter calculation module, saturation control module, hue control module, luminance control module, and inverse color space conversion module. Each module handles a specific aspect of color transformation, allowing precise control over saturation and hue while mapping between different color gamuts, thereby preventing contour phenomenon and color fading.
Solution Approach 2:
The patent applies different control strategies to different regions of the color space. The saturation control module and hue control module adjust parameters locally based on the specific chrominance components (Cb, Cr) and calculated hue angles, ensuring that each region of the color gamut is mapped with appropriate quality rather than applying a uniform transformation across the entire color space.
2Measurement precision
If precise color gamut tuning is performed to improve color accuracy, then color reproduction quality is improved, but contour phenomenon occurs in gray gradation areas
Solution Approach 1:
The patent extracts and separately processes the luminance component (Y) from the chrominance components (Cb, Cr) through color space conversion. The luminance control module then independently adjusts the luminance component based on grayscale differences, separating the luminance adjustment from chrominance adjustment to prevent contour phenomenon in gray gradation areas while maintaining color accuracy.
Solution Approach 2:
The hue calculation module calculates hue angles from chrominance components before saturation and hue control are applied. The parameter calculation module pre-calculates appropriate saturation gains and hue gains based on these hue angles and selected hue axes, preparing correction parameters in advance to guide the subsequent saturation controller and hue controller, ensuring precise color tuning without artifacts.
Data Source
AI summary
The present disclosure relates to a color gamut mapping method and a color gamut mapping device. A color gamut mapping method may include converting, by a color space converter, first three-color signals into a first luminance component and a pair of first chrominance components and outputting the first luminance component and the pair of first chrominance components, controlling, by a saturation controller, a saturation of the first chrominance component for each control area using a saturation gain of the saturation controller and outputting a second chrominance component, controlling, by a hue controller, a hue of the second chrominance component for each control area and outputting a third chrominance component, interpolating, by an overall controller, a set value of a luminance gain using grayscale differences between the first three-color signals, outputting a second luminance component by controlling first luminance component using the interpolated luminance gain.