Color Conversion Accuracy via Black Component Segmentation
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Solution Overview
Problem
The accuracy of color conversion from device-dependent color spaces, such as RGB, to device-independent color spaces, like Lab, is compromised when a color patch includes a black component (K color component), leading to non-linear corresponding relationships and reduced conversion accuracy.
Innovation Solution
An image processing device that accepts read data in a device-dependent color space, reference data in a device-independent color space, and specific color component data to generate conversion information, distinguishing between data with and without a K color component, thereby improving the accuracy of color conversion by using separate conversion models or look-up tables for each type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a color patch includes a black component (K color component) for generating conversion information, then the color gamut is expanded and more colors can be represented, but the accuracy of color conversion from device-dependent color space to device-independent color space is lowered due to non-one-to-one correspondence between RGB data and Lab data
Solution Approach 1:
The patent segments the color conversion process into two distinct paths: one for color patches containing the black component and another for color patches without the black component. By dividing the conversion information generation into separate segments based on the presence of the black component, the system maintains accurate one-to-one correspondence in each segment while still supporting the full color gamut including black-containing colors.
Solution Approach 2:
The patent applies different conversion information locally based on whether the black component is present. Instead of using a single universal conversion method, the system generates and applies specific conversion information tailored to each case (with or without black component), ensuring optimal accuracy for each local condition while maintaining overall system versatility.
2Adaptability or versatility
If multiple color patches with different CMYK combinations are used to generate conversion information, then the color representation capability is improved, but the conversion accuracy is reduced because different CMYK combinations can produce the same Lab values, creating non-linear correspondence
Solution Approach 1:
The patent segments the set of color patches into two distinct groups: those containing the black component and those without. This segmentation allows the system to handle the non-linear correspondence issue by treating black-containing patches separately, ensuring that conversion information is generated only from patches with unique, linear RGB-to-Lab correspondence.
Solution Approach 2:
The patent changes the selection criterion for generating conversion information from merely 'color diversity' to 'color uniqueness with respect to RGB data'. By modifying the parameter that determines which color patches are used for conversion information generation, the system eliminates the non-linear correspondence problem while preserving adequate color representation capability.
Data Source
AI summary
An image processing device includes an accepting unit, and a conversion information generating unit. The accepting unit accepts items of read data in a device-dependent color space that are generated by reading color patches, items of reference data in a device-independent color space of the color patches, and items of specific color component data each indicating a specific color component in a corresponding one of the color patches. The conversion information generating unit generates conversion information reflecting the presence or amount of a specific color component included in each color patch as information for converting input data in the device-dependent color space to output data in the device-independent color space, on the basis of the items of read data, the items of reference data, and the items of specific color component data.