Dynamic Color Mapping for Printer Gamut Chroma and Difference
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Solution Overview
Problem
Existing color mapping methods in printers result in chroma lowering or color difference loss, particularly when dealing with colors outside the printer's reproduction color gamut, and fail to account for spatially adjacent colors that may appear differently due to mapping.
Innovation Solution
An image processing apparatus and method that dynamically switches between 'perceptual' and 'colorimetric' mapping based on the presence of colors within the printer's gamut, and adjusts mapping for spatially adjacent pages to minimize chroma loss and color difference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If perceptual mapping is used to map colors to printer gamut, then color difference is reduced, but chroma is lowered
Solution Approach 1:
The patent applies different mapping strategies to different color regions and spatial locations. For colors within the printer gamut, colorimetric mapping is used to preserve chroma. For colors outside the gamut, perceptual mapping is applied to reduce color difference. This local differentiation resolves the contradiction by optimizing for the appropriate criterion in each specific case rather than using a single global mapping approach.
Solution Approach 2:
The patent dynamically switches between perceptual and colorimetric mapping based on the specific color values and their position relative to the printer gamut. The mapping method is not fixed but adapts in real-time according to the input color data, allowing the system to maintain chroma when possible and reduce color difference when necessary.
2Reliability
If colorimetric mapping is used to preserve chroma, then chroma is maintained, but color difference increases for colors outside gamut
Solution Approach 1:
The system applies colorimetric mapping specifically to color regions within the printer gamut where chroma preservation is critical, while switching to perceptual mapping for out-of-gamut colors where color difference reduction is more important. This localized application of different mapping qualities resolves the contradiction.
3Productivity
If mapping is performed for each page independently, then processing speed is improved, but visual consistency across adjacent pages deteriorates
Solution Approach 1:
The patent segments the processing into two levels: color mapping is performed independently for each page to maintain processing speed, but a separate spatial consistency check is performed across adjacent pages to ensure visual coherence. This segmentation allows both fast processing and consistency to be achieved at different processing stages.
Solution Approach 2:
The system performs feedback checking across spatially adjacent pages to detect and correct visual inconsistencies that may arise from independent page processing. This feedback mechanism ensures that while processing remains efficient, the final output maintains visual consistency across page boundaries.
Data Source
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AI summary
An image processing apparatus (10) comprising: decision means for deciding a first color mapping method to a print color gamut for a first partial original based on a pixel value included in the first partial original and the print color gamut of a print unit and decide a second color mapping method to a print color gamut for a second partial original based on a pixel value included in the second partial original and the print color gamut of the print unit; and a color conversion means for performing color conversion of the first partial original by the first color mapping method decided, and perform color conversion of the second partial original by the second color mapping method decided.