Color Gamut Mapping for LCDs Using LCH Parameter Segmentation
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Solution Overview
Problem
Conventional color gamut mapping methods fail to minimize perceived color differences and maintain brightness and contrast, particularly when transitioning between standard RGB and wide color gamuts, due to neglecting hue variations and gamut shapes and sizes.
Innovation Solution
A color gamut mapping method that converts image data into lightness, chroma, and hue components, adjusts the primary hue angle, rebuilds the gamut boundary, decides a multifocal point, and applies varying mapping slopes to minimize color differences and maintain lightness and contrast by considering the original and reproduction gamut's size, shape, and position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional color gamut mapping method is used to compress or extend color gamut, then color gamut mapping is achieved, but color difference perceived by person increases and color reproducibility deteriorates
Solution Approach 1:
The patent changes the parameter representation from conventional RGB or simple chromaticity coordinates to LCH (Lightness-Chroma-Hue) color space parameters. By transforming color data into lightness, chroma, and hue components, the mapping process can independently adjust each parameter to minimize perceived color differences while achieving accurate gamut compression or extension.
Solution Approach 2:
The patent segments the color gamut mapping process into distinct stages: converting image data to LCH parameters, separately adjusting lightness and chroma components, and then reconstructing the color data. This segmentation allows precise control over different aspects of color perception, improving overall color reproducibility.
2Manufacturing precision
If conventional color gamut mapping method is used, then gamut compression or extension is achieved, but brightness and contrast deteriorate
Solution Approach 1:
The patent independently controls the lightness parameter separate from chroma and hue parameters. By adjusting only the chroma and hue components for gamut mapping while preserving the lightness component, the method maintains brightness and contrast characteristics of the original image while achieving accurate color gamut compression or extension.
Solution Approach 2:
The patent segments color data into lightness, chroma, and hue components, allowing independent processing of each aspect. The lightness component is preserved to maintain brightness and contrast, while chroma and hue are adjusted for accurate gamut mapping, resolving the contradiction between color accuracy and brightness preservation.
3Manufacturing precision
If conventional color gamut mapping method is used, then color gamut mapping is achieved, but hue variation is not considered and specific color accuracy deteriorates
Solution Approach 1:
The patent introduces hue as a separate independent parameter in the LCH color space representation. By explicitly modeling hue variation, the mapping process can accurately adjust hue values to match the reproduction gamut while minimizing perceived color differences, particularly for sensitive hues like blue.
Data Source
AI summary
A color gamut mapping method, which is capable of minimizing a color difference perceived by a person, preventing brightness and contrast from deteriorating, and improving color reproducibility, and a liquid crystal display device using the same are disclosed. The color gamut mapping method includes converting image data having an original gamut into lightness, chroma and hue data, adjusting a primary hue angle of the original gamut according to a reproduction gamut and adjusting the hue data according to the adjustment amount of the primary hue angle, changing the lightness of an original gamut boundary in consideration of a reproduction gamut boundary and changing the brightness data by the change amount of the lightness of the original gamut boundary, deciding a focal point, which is a reference point of color gamut mapping, according to the size, the shape and the position of the original/reproduction gamut in lightness and chroma coordinates, deciding a mapping slope according to the decided focal point FP and a mapping area in which the lightness and chroma data are located and mapping the original gamut to the reproduction gamut according to the decided mapping slope, and converting the lightness, chroma and hue data mapped to the reproduction gamut into image data.