Selective Trapping for Multicolor Images
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Solution Overview
Problem
In multicolor printing, the trapping process often generates unwanted color components when figures are allocated with overlapping positions, leading to unnatural color allocations, especially in images with gradations of color density.
Innovation Solution
A method that specifies and extracts a skeleton of the boundary figure by identifying the first portion in contact with a figure above the objective figure and the second portion in contact with a figure below it, allowing for the allocation of a trap figure only where colors appear adjacent, thus preventing unwanted color components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a trap figure is allocated to all boundary portions between an objective figure and lower figures, then gaps at boundary portions are prevented, but unwanted color components are generated when figures are allocated with overlapping positions
Solution Approach 1:
The patent applies local quality by differentiating the treatment of boundary portions based on their spatial context. Specifically, when a figure is allocated to the upper side of the objective figure, the boundary portion between the objective figure and the lower figure is excluded from trap figure allocation. This selective approach ensures that trap figures are only allocated where they produce the desired effect (preventing gaps) without causing unwanted color components in overlapping regions.
2Extent of automation
If trapping process is executed in units of figures constituting the image, then the process can be automated on a computer, but trap figures containing unwanted color components are generated in overlapping configurations
Solution Approach 1:
The patent implements feedback by having the computer-based trapping process check the allocation status of figures before generating trap figures. Specifically, the system determines whether a figure is allocated to the upper side of the objective figure, and based on this feedback information, selectively excludes certain boundary portions from trap figure allocation. This automated feedback mechanism prevents unwanted color components while maintaining computer-based automation.
3Reliability
If a trap figure is allocated to boundary portions in images with gradation of color density, then gap prevention is achieved, but the natural appearance of the image is degraded due to unwanted color components
Solution Approach 1:
The patent applies local quality by selectively treating boundary portions in gradation images based on figure allocation. When figures are allocated with overlapping positions, the boundary portions between the objective figure and lower figures are excluded from trap figure allocation. This selective approach preserves the natural appearance of gradation images by preventing unwanted color components while still providing gap prevention where figures are not overlapping.
Data Source
AI summary
In trapping process of a multicolor image, an adjacent vector between an objective figure and a relative figure at an upper side is specified first. Then, with the use of the contour of the objective figure except for this adjacent vector, an adjacent vector between the objective figure and a lower relative figure is extracted. This enables to extract, as an adjacent vector, only the portion at which the color of the objective figure and the color of the lower related figure are adjacent each other in appearance. Therefore, the trapping process is executable without generating any unwanted color component on the image.