Blue Noise Dither Pattern Generation for Dot Dispersibility
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Solution Overview
Problem
Existing dither pattern generation methods struggle to achieve high dispersibility for both single-color and mixed-color printing, often resulting in reduced dispersibility and increased granular feeling due to dot overlap, especially in low-gradation areas.
Innovation Solution
A method for generating plural dither patterns with blue noise characteristics, where threshold values are set to prioritize high dot concentration ratios in both initial and combined dot patterns, ensuring high dispersibility and minimizing dot overlap across colors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dither patterns are generated considering only single-color printing, then dispersibility for single-color is improved, but dispersibility for mixed-color printing deteriorates due to dot overlap
Solution Approach 1:
The patent divides the dither pattern generation into two separate processes: one optimized for single-color printing and another for mixed-color printing. By segmenting the solution, each dither pattern can be specifically optimized for its intended use case, resolving the contradiction between single-color dispersibility and mixed-color adaptability
Solution Approach 2:
The patent makes the dither pattern selection dynamic by providing different dither patterns based on the printing mode (single-color or mixed-color). This dynamic adaptation allows the system to achieve optimal dispersibility for each specific printing scenario, rather than using a fixed pattern that compromises both scenarios
2Productivity
If quantization processing is performed for each color independently, then processing speed is improved, but dot dispersibility deteriorates due to overlapping dots of different colors
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing separate dither patterns for single-color and mixed-color printing before actual printing occurs. During printing, the appropriate pre-prepared pattern is simply selected and applied, maintaining high processing speed while ensuring optimal dispersibility for the specific printing mode
Solution Approach 2:
The patent applies local quality by using different dither patterns specifically tailored for different printing modes. The dither pattern for mixed-color printing is designed with consideration for inter-color dot distribution, while the single-color pattern optimizes for intra-color dispersibility, giving each local situation its appropriate treatment
3Manufacturing precision
If threshold values are set to maximize dot concentration, then image quality is improved, but granular feeling increases due to dot clustering in low-gradation areas
Solution Approach 1:
The patent changes the threshold value parameters in the dither pattern based on the printing mode. By adjusting the threshold distribution in the dither patterns, the system can achieve high dot concentration where needed while maintaining adequate spacing in low-gradation areas, thus improving image quality without excessive granular feeling
Data Source
AI summary
Provided is a dither pattern generation method so that a dot arrangement having excellent dispersibility can be obtained in low-gradation areas for single colors and for mixed colors. The dither pattern generation method generates dot patterns for low-gradation areas having threshold values 1 to S so that high dispersibility is obtained in a cyan dot pattern and a magenta dot pattern, and so that in a combined dot pattern made by combining these dot patterns there are no overlapping pixels. The dither pattern generation method then sets threshold values for a cyan dither pattern and a magenta dither pattern based on these generated dot patterns.