Color Matching Method for Luminous Intensity Preservation
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Solution Overview
Problem
Current color matching methods between different polychromatic displays, such as RGB and RGBW, face challenges in accurately converting colors due to non-overlapping color gamuts, leading to issues like overflow, loss of contrast, and degradation of color accuracy, especially when dealing with colors outside the gamut.
Innovation Solution
A color matching method that prioritizes luminous intensity by transforming signals to corresponding luminous intensity values, using gamma correction and additional processes to handle overflow values, and adding extra white to maintain luminance when colors are outside the gamut, while considering the characteristics of human visual perception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional color matching methods are used to convert colors between RGB and RGBW displays, then color conversion can be performed, but color accuracy deteriorates due to non-overlapping color gamuts causing overflow and clipping
Solution Approach 1:
The patent transforms the color conversion problem from direct RGB to RGBW mapping by changing the parameter space to luminous intensity values. This involves converting RGB signals to luminous intensity values through gamma correction, then calculating RGBW luminous intensities that match the source while avoiding gamut overflow. This parameter transformation enables accurate representation of colors outside the target gamut.
Solution Approach 2:
The patent moves from three-dimensional RGB color space to four-dimensional RGBW color space by adding the white channel dimension. This dimensional expansion allows the system to represent colors that would otherwise overflow in the target gamut, particularly by utilizing the white channel to maintain luminance while adjusting chrominance.
2Ease of operation
If clipping is applied to handle overflow values in conventional color matching, then valid range constraints are satisfied, but color information is lost and contrast deteriorates
Solution Approach 1:
The patent converts the harmful effect of gamut overflow into a beneficial feature by intentionally allowing luminous intensity values to exceed the target gamut limits. Instead of clipping these values, the method uses them to maintain accurate luminance representation, and the white channel compensates for the chrominance overflow, thereby preserving color information that would otherwise be lost.
Solution Approach 2:
The patent introduces luminous intensity values as an intermediary between the source RGB signals and the target RGBW outputs. This intermediary representation in the luminous intensity domain allows for accurate transformation while maintaining the ability to recover the original color information, preventing the data loss that occurs with direct clipping in the RGB domain.
3Manufacturing precision
If re-mapping is used to preserve hue and saturation, then chrominance is maintained, but luminous intensity information is sacrificed
Solution Approach 1:
The patent inverts the conventional approach by prioritizing luminous intensity matching over chrominance matching. Instead of preserving hue and saturation at the expense of luminance, the method first ensures accurate luminous intensity representation and then derives chrominance values that are consistent with both the source color and the matched luminance, achieving a different but equally valid color matching objective.
Data Source
AI summary
The invention relates to a color matching method for transforming a color representation of a first set of color primaries with a plurality of first signals to a second set of color primaries with a plurality of second signals in a first domain. The color matching method of the invention is to consider the characteristics of human visual perception. Since human is more sensitive to the luminous intensity than chrominance, the color matching method of the invention is considered to match the luminous intensity. The color matching method of the invention can minimize the intensity difference by utilizing the optimality of resource distribution. An additional step of smoothing the intensity difference among color primaries at the level of color primaries is appended. It enhances the visual quality especially for the images with a gradual change in numerous levels of color. Besides, when the color is outside the gamut, we keep the information of luminance by adding extra white. According to the invention, the color matching method of handling colors outside gamut can provide a higher contrast which is especially good for displaying a color change with numerous levels, such as sunrise or sunset scenes. The color matching method further considers color interactions of each color primary regarding the configuration of surrounding color primaries. With the consideration of exploiting the perceived luminous intensity instead of physical luminous intensity, a superior color matching algorithm can be made.