Color Conversion Table Creation for Accurate Multi-Device Matching
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Solution Overview
Problem
Current color conversion techniques for image data in printing lack sufficient accuracy and versatility, especially when printing characteristics between reference and user printers differ significantly, requiring manual correction and extensive trial-and-error, and are limited by one-dimensional color correction methods.
Innovation Solution
A color conversion table creation device and method that reads target and printed matter images, performs multi-dimensional color conversion using input and output color conversion tables, and creates a color conversion table based on chromaticity values to achieve accurate color matching and management, even when the target profile is unknown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one-dimensional color correction for each RGB color component is used, then the correction process is simple, but the color correction accuracy deteriorates when printing characteristics of reference and user printers are significantly different
Solution Approach 1:
The patent transitions from one-dimensional color correction (treating each RGB component independently) to multi-dimensional color correction by considering the combined relationships of multiple color components. This is achieved by creating color conversion tables that map correspondence between multiple color components simultaneously, enabling accurate color correction even when printing characteristics differ significantly between reference and user printers.
2Manufacturing precision
If manual correction of image data and adjustment of printing conditions are performed, then color matching can be achieved, but a large amount of time and effort is required
Solution Approach 1:
The patent performs preliminary color conversion table creation by automatically calculating correspondence relationships between color components of reference and user printers. This pre-computed color conversion table enables direct color correction without requiring manual trial-and-error adjustment, significantly reducing the time and effort needed for color matching while maintaining high accuracy.
Solution Approach 2:
The system enables self-service color correction by automatically generating color conversion tables based on scanner readings of color charts. The color correction process is automated through algorithmic calculation of correspondence relationships, eliminating the need for manual operator intervention in color matching tasks.
3Measurement precision
If color tone conversion parameters are calculated sequentially through printer, scanner, and printer correspondence, then individual device correction is achieved, but versatility as a color profile is limited
Solution Approach 1:
The patent creates color conversion tables that serve multiple functions: they can be used for correcting individual printer devices, for scanner calibration, and for cross-device color matching. The correspondence relationship data structure is designed to be versatile, enabling the same color conversion table to address various color management scenarios beyond just individual device correction.
Data Source
AI summary
A color conversion table creation device includes: an image reading unit that reads a target printed matter and a printed matter printed by a printing device to acquire read image data indicating a read image of each of the target printed matter and the printed matter; a first color conversion unit that converts, using a first color conversion table indicating a correspondence relationship between a signal value in a first color space acquired by the image reading unit and a chromaticity value in a second color space which is a device-independent color space, the signal value in the first color space into the chromaticity value in the second color space; and a second color conversion unit that color-converts document image data into print image data using an input color conversion table and an output color conversion table.