Dot Pattern Adjustment for Image Granularity Reduction
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Solution Overview
Problem
Conventional image forming apparatuses using FM screening for pseudo continuous tone reproduction face issues with granularity due to overlapping dot patterns of C and M colors, leading to a feeling of roughness in skin color portions of images, especially when observed at close distances.
Innovation Solution
An image forming apparatus and dot pattern adjustment method that generates a second dot pattern based on the positional relationship of the first dot pattern, adjusting dot positions to reduce overlapping by using Delaunay triangles and Voronoi tessellation, ensuring a uniform dot arrangement and reducing the ratio of overlapping dot patterns of C and M colors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If FM screening with random dot arrangement is used, then resistance to streak-like noise is improved, but visual smoothness deteriorates due to feeling of roughness from irregular density changes
Solution Approach 1:
The patent applies local quality by making dot arrangements color-specific rather than uniformly random. Each color (C, M, Y, K) has its own predetermined dot arrangement pattern, creating locally optimized quality for each color channel while maintaining overall FM screening benefits against streak noise.
Solution Approach 2:
The patent uses preliminary action by pre-defining specific dot arrangements for each color before the actual printing process. These predetermined patterns are stored and retrieved during printing, eliminating the need for complex real-time random generation and ensuring consistent visual smoothness across prints.
2Manufacturing precision
If dot patterns of C and M colors are overlapped to express skin color, then color accuracy is improved, but granularity increases due to overlapping dot patterns causing radical density changes
Solution Approach 1:
The patent applies local quality by creating color-specific dot arrangements where C, M, Y, and K colors have distinct predetermined patterns. This ensures that when colors overlap to form skin tones, the overlapping is controlled and uniform rather than creating radical density changes that cause granularity.
3Object-affected harmful factors
If multiple dot patterns are generated and processed simultaneously to reduce overlapping, then visual smoothness is improved, but processing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the dot pattern generation into separate predetermined patterns for each color (C, M,Y, K). Instead of generating and processing multiple patterns simultaneously, the system uses pre-segmented color-specific patterns that are simply retrieved and overlaid during printing, greatly reducing processing complexity.
Data Source
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AI summary
An image forming apparatus (1) includes an image forming section (20), and a pattern generating section (100) that generates a dot pattern. In a case where a first dot pattern of a first color with a uniform density and a second dot pattern of a second color with a uniform density are combined, the pattern generating section adjusts the second dot pattern based on a positional relationship of each dot in the first dot pattern.