Image Density Correction Using Unified Color Mixture Proportion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image forming apparatuses face density unevenness issues in image formation, leading to imbalanced color mixture proportions between cyan, magenta, yellow, and black colors, which disrupts gray balance and color balance.
Innovation Solution
An image processing device and method that corrects density unevenness by calculating correction values for each color based on measurement data from patch images at multiple positions in the main and sub-scanning directions, using a storage part to store target values and color mixture proportion information, and applying these corrections to pixel density values in image data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If density unevenness correction is performed for each color (C, M, Y, K) separately, then density unevenness in each color is corrected, but the color mixture proportion becomes unbalanced and gray balance is disturbed
Solution Approach 1:
The patent merges the density correction processes for different colors by using a unified correction table that is constructed and applied across all colors (C, M, Y, K). Instead of separate correction tables for each color, a single correction table is created using patch images containing multiple colors, and this unified table is then applied to correct density unevenness while maintaining color balance relationships.
Solution Approach 2:
The correction table serves multiple functions simultaneously: it corrects density unevenness for all colors, maintains gray balance, and preserves color mixture proportions. The patch images used to construct the correction table contain multiple colors at different positions, allowing the single table to capture and correct density variations across the entire color spectrum while maintaining relative color relationships.
2Measurement precision
If patches with the same density are generated at multiple positions to measure density values, then density unevenness can be detected, but the measurement process becomes complex and time-consuming
Solution Approach 1:
The patent combines multiple patch images with different colors and positions into a single correction chart that can be measured once. This correction chart contains patches of C, M, Y, and K colors at various positions, allowing simultaneous measurement of density characteristics for all colors and positions in a single measurement process, thereby reducing complexity while maintaining precision.
Solution Approach 2:
The correction chart is prepared in advance with pre-positioned patches of different colors and densities at specific locations. This preliminary arrangement of patches allows the measurement device to capture density information for multiple positions and colors in a single measurement operation, eliminating the need for separate measurements for each color and position.
Data Source
AI summary
Disclosed is an image processing device comprising: a storage part to store a target value set for each tone value in a plurality of colors; a measurement value information obtaining part to obtain measurement value information, the measurement value information comprising a measurement value of a density at each of a plurality of measurement positions in a main and a sub-scanning directions; a correction target value calculation part to correct the target value based on color mixture proportion information where a proportion of the colors is set, and to calculate a correction target value; a correction value calculation part to calculate a correction value of the density at each measurement position, which is calculated based on the correction target value and the measurement value information; and a correction part to correct a density value of each pixel in image data, based on the correction value.