Image Processing Apparatus Reducing Granularity via Segmented Threshold Matrices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image processing methods for printing with multiple color materials result in conspicuous granularity due to the arrangement of overlapping dots, even when using threshold matrices with blue noise characteristics, particularly for cyan and magenta colors.
Innovation Solution
An image processing apparatus that generates quantization data for each color based on unique threshold matrices with inverse pixel position orders, allowing for the generation of quantization data with fewer gradations and optimizing dot dispersibility by adjusting thresholds and gradation data comparison methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a common threshold matrix with blue noise characteristics is used for multiple color materials, then good dot dispersibility is obtained for single-color printing, but conspicuous granularity occurs in mixed-color printing due to overlapping dots
Solution Approach 1:
The patent divides the threshold matrix into separate color-specific threshold matrices (first threshold matrix for cyan, second threshold matrix for magenta, etc.). Each color channel uses its own threshold matrix, allowing independent optimization of dot dispersibility for each color while avoiding the granularity problem that occurs when using a common threshold matrix for multiple colors.
Solution Approach 2:
The patent assigns different threshold matrices to different color channels based on their specific characteristics. Each color (cyan, magenta, yellow, black) has its own optimized threshold matrix that considers the dot power and visual sensitivity of that specific color, enabling local optimization rather than a one-size-fits-all approach.
2Ease of operation
If quantization processing is performed with a single threshold matrix for multiple colors, then processing simplicity is maintained, but dot dispersibility deteriorates for colors with high dot power
Solution Approach 1:
The patent segments the quantization processing into separate operations for each color channel, with each channel using its own optimized threshold matrix. This segmentation allows each color to be processed independently with optimal parameters, improving dot dispersibility while maintaining reasonable processing complexity through modular design.
Solution Approach 2:
The patent changes the threshold parameters specifically for colors with high dot power (cyan and magenta) by using separate threshold matrices optimized for these colors. This parameter optimization ensures that colors with higher dot power achieve better dot dispersibility without affecting the processing of other colors.
Data Source
AI summary
When a sum of a first gradation data for a first color and a second gradation data for a second color is greater than the maximum value of thresholds of a first threshold matrix, a generation unit generates a first overlapping gradation data and second overlapping gradation data by dividing a value obtained by subtracting the maximum value from the sum. Further, the generation unit generates a first quantization data based on a result of comparing the first overlapping gradation data with the second threshold or a result of comparing a difference between the first gradation data and the first overlapping gradation data with the first threshold, and generates a second quantization data based on a result of comparing the second overlapping gradation data with the first threshold or a result of comparing a difference between the second gradation data and the second overlapping gradation data with the second threshold.