Gamut Adaptation via Chromaticity-Dependent Mapping Angle
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Solution Overview
Problem
Existing color processing algorithms fail to effectively map video signals to wider gamut displays, leading to suboptimal color reproduction, especially when the input gamut includes colors not present in the reproduction gamut, and do not utilize the full potential of new displays.
Innovation Solution
A system that transforms input colors within a first gamut into reproduction colors for a second gamut by adjusting lightness and chromaticity, using a mapping angle that depends on chromaticity and lightness to enhance contrast and chromaticity, while avoiding unnatural color shifts, and includes a color look-up table for efficient implementation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If colorimetric mapping is applied to transform input colors to reproduction colors, then color accuracy is improved, but chromaticity enhancement is limited
Solution Approach 1:
The patent changes the parameters of color transformation by introducing a mapping angle that varies with chromaticity and lightness. Instead of using fixed colorimetric mapping, the system dynamically adjusts the transformation parameters based on the input color characteristics, enabling both accurate color reproduction and enhanced chromaticity for saturated colors.
Solution Approach 2:
The patent makes the color mapping dynamic by using a mapping angle that depends on chromaticity and lightness values. The transformation is not static but adapts to the input color properties, allowing the system to enhance chromaticity for saturated colors while maintaining accuracy for other colors.
2Adaptability or versatility
If chroma enhancement is applied to all colors, then saturation is improved, but unnatural color shifts occur for low-chromaticity colors
Solution Approach 1:
The patent applies local quality by differentiating the treatment of colors based on their chromaticity. The mapping angle varies with chromaticity, so that chroma enhancement is applied selectively to saturated colors while low-chromaticity colors undergo minimal transformation, preventing unnatural color shifts.
Solution Approach 2:
The system changes the transformation parameter (mapping angle) based on the chromaticity of the input color. This dynamic parameter adjustment ensures that chroma enhancement is applied only where appropriate, maintaining natural appearance for low-chromaticity colors while enhancing saturation for high-chromaticity colors.
3Device complexity
If the same drive values are used for wide-gamut display, then device complexity is reduced, but color reproduction potential is not exploited
Solution Approach 1:
The patent introduces a parameter change approach by using a mapping angle that varies with chromaticity and lightness. This dynamic transformation allows the system to exploit the full color reproduction potential of wide-gamut displays while keeping the processing relatively simple through the use of lookup tables and mathematical transformations.
Data Source
AI summary
A system (600) for performing gamut compression or gamut extension by transforming an input color (608) of an input image defined within a first gamut (102) into a reproduction color (610) of an output image for rendering by a reproduction device capable of rendering colors within a second gamut (104) different from the first gamut. The input color has an input chromaticity (C1) and an input lightness (Z-*) together forming an input point (202) in a chromaticity-lightness plane. The reproduction color has a reproduction point (210) in the chromaticity-lightness plane, wherein an absolute difference between the input lightness and the output lightness is a decreasing function of at least the chromaticity. An absolute difference between the input chromaticity and the output chromaticity is an increasing function of at least the chromaticity.