Threshold Matrix Switching for Inter-Scan Misregistration
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Solution Overview
Problem
Existing image processing technologies face challenges in maintaining image quality due to inter-scan misregistration during the printing process, particularly in environments where printhead scans deviate in landing position, leading to graininess and reduced robustness.
Innovation Solution
An image processing apparatus that generates print data using a threshold matrix based on tone values, switching between different threshold matrices for each scan to minimize dot arrangement overlap and maintain exclusive relationships between scans, thereby reducing the impact of inter-scan misregistration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single threshold matrix is used for all scans, then the processing is simple, but image quality deteriorates due to inter-scan misregistration
Solution Approach 1:
The patent divides the threshold matrix selection into multiple segments based on tone value ranges. Different threshold matrices are selected for different tone ranges (first threshold matrix for lower tones, second threshold matrix for higher tones), which segments the quantization process to handle inter-scan misregistration differently across various density regions, thereby improving image quality while managing complexity through structured segmentation.
Solution Approach 2:
The patent implements dynamic threshold matrix selection based on the tone value of the input signal. The system dynamically switches between first and second threshold matrices depending on whether the tone value falls within the first or second range, making the quantization process adaptive to different tonal conditions and reducing the impact of inter-scan misregistration across varying image regions.
2Reliability
If threshold matrices are selected based on tone value ranges, then robustness to inter-scan misregistration improves, but processing complexity increases
Solution Approach 1:
The patent changes the threshold matrix parameter based on the tone value parameter. By determining which threshold matrix to use (first or second) according to whether the tone value is in the first or second range, the system adapts the quantization parameters to the current tonal conditions, improving robustness to inter-scan misregistration through parameter adaptation rather than complex processing.
3Manufacturing precision
If multiple threshold matrices are used for different tone ranges, then graininess and robustness improve, but the processing load increases
Solution Approach 1:
The patent applies different threshold matrices to different local regions of the image based on their tone values. The first threshold matrix is applied to regions with lower tone values while the second threshold matrix is applied to regions with higher tone values, allowing each region to receive optimized quantization treatment that improves graininess and robustness locally without requiring uniform high-processing-cost treatment across the entire image.
Data Source
AI summary
A quantization unit executes quantization processing for first print data corresponding to a first scan using a first threshold matrix and a third threshold matrix, and executes the quantization processing for second print data corresponding to a second scan using a second threshold matrix and a fourth threshold matrix, and a first degree that a dot arrangement that is a result of quantization using the third threshold matrix and a dot arrangement that is a result of quantization using the fourth threshold matrix hold an exclusive relationship is smaller than a second degree that a dot arrangement that is a result of quantization using the first threshold matrix and a dot arrangement that is a result of quantization using the second threshold matrix hold the exclusive relationship.