Dither Pattern Generation for Dot Dispersibility
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Solution Overview
Problem
Existing dither patterns used in image processing may lose dot dispersibility and increase graininess due to variations in printing controls and time-divisional driving, especially when printing at higher resolutions or under limited power supply conditions.
Innovation Solution
A method to generate a dither pattern that accounts for potential dot position changes by setting thresholds for pixel areas in a way that maintains high dispersibility, using a flowchart process to adjust thresholds based on dot concentration, ensuring excellent dot dispersibility and reduced graininess even with index development processing and time-divisional driving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a dither pattern is generated using conventional methods, then the processing load is reduced and dot arrangement is visually favorable, but dot dispersibility is lost and graininess increases due to printing control variations
Solution Approach 1:
The patent applies preliminary action by generating multiple dither patterns in advance, each corresponding to different printing conditions (e.g., different numbers of print passes, different dot placement strategies). These pre-generated patterns are stored and selected based on the actual printing conditions, ensuring that the appropriate dither pattern is ready before printing occurs, thus maintaining dot dispersibility without increasing real-time processing load
Solution Approach 2:
The patent implements dynamics by making the dither pattern selection adaptive to actual printing conditions. Instead of using a fixed dither pattern, the system dynamically selects from multiple pre-generated patterns based on parameters such as the number of print passes, dot placement constraints, and printing resolution, allowing the system to adapt to varying manufacturing conditions while maintaining dot dispersibility
2Measurement precision
If printing is performed at higher resolution, then image quality is improved, but dot position variations increase and blue noise properties are lost
Solution Approach 1:
The patent applies local quality by generating different dither patterns tailored to specific local printing conditions. Each dither pattern is designed with specific characteristics suitable for particular printing scenarios (e.g., single-pass vs. multi-pass printing, different resolution levels). This allows each local region of the image to receive the most appropriate dither pattern for its specific printing conditions, maintaining dot dispersibility while accommodating higher resolution requirements
Solution Approach 2:
The patent implements parameter changes by varying the dither pattern parameters (threshold values, pattern structures) based on printing resolution and conditions. The system adjusts dither pattern characteristics to match the printing resolution and other parameters, ensuring that the dither pattern remains effective regardless of whether printing is performed at high or low resolution, thus maintaining dot dispersibility across different quality levels
3Use of energy by moving object
If time-divisional driving is used to control printing elements, then power consumption is reduced, but dot position displacement occurs and dispersibility is compromised
Solution Approach 1:
The patent applies preliminary action by pre-generating dither patterns that account for the effects of time-divisional driving. The dither patterns are designed in advance to compensate for the displacement that will occur during sequential printing element activation. This allows the system to maintain dot dispersibility even when time-divisional driving causes position variations, without requiring additional real-time correction processing
Solution Approach 2:
The patent implements preliminary anti-action by designing dither patterns that counteract the harmful effects of time-divisional driving before printing occurs. The patterns are constructed to compensate for the displacement that will happen during sequential printing, effectively neutralizing the adverse effect of time-divisional driving on dot dispersibility while maintaining the energy savings benefits
Data Source
AI summary
Formed is a dither pattern that makes it possible to output an image with excellent dot dispersibility and reduced graininess regardless of controls after quantization processing. To this end, an extended pattern in which multiple divided pixels correspond to each of multiple pixels included in quantization data and one or more of the multiple divided pixels are determined as dot-arrangeable-pixels in which dots can be printed is generated. Thereafter, the thresholds of the dither pattern are set based on the extended pattern in which the dots are arranged to obtain predetermined dispersibility.