Color Correction Table Creation Using Reference Device and Spline Interpolation
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Solution Overview
Problem
Existing color correction table methods fail to accurately correct colors in mixed color areas, especially when using a small number of measured colors, leading to interpolation inaccuracies.
Innovation Solution
A method for creating a color correction table that uses a reference printing apparatus to acquire device-dependent values, establishing a relationship between input and correction values, and supplementing deficient data with a spline function to achieve high accuracy, even with a small number of measured colors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If color correction table is created independently for each ink color, then the creation process is simple, but errors in mixed color area cannot be sufficiently corrected
Solution Approach 1:
The patent merges the correction processes for different ink colors by creating a single color correction table that simultaneously corrects multiple color components (CMYK). Instead of creating separate correction tables for each ink color, the invention combines them into one unified table that handles mixed color areas effectively, resolving the contradiction between simplicity and accuracy.
2Measurement precision
If the number of measured colors is increased to improve interpolation accuracy in mixed color area, then interpolation accuracy improves, but the measurement workload increases exponentially
Solution Approach 1:
The patent changes the approach from measuring many color points to measuring fewer color points and using a mathematical model (interpolation function) to calculate the remaining values. By changing from a brute-force measurement approach to a model-based calculation approach, the invention achieves high interpolation accuracy without requiring exponential increase in measured colors.
Solution Approach 2:
The patent performs preliminary measurements on a limited set of color patches and uses these measurements to build an interpolation function that can predict values for all other colors. This preliminary action with few measurements enables accurate interpolation across the entire color space without requiring exhaustive measurement of all possible color combinations.
3Productivity
If interpolation is performed with a small number of measured colors, then the measurement workload is reduced, but interpolation accuracy deteriorates
Solution Approach 1:
The patent introduces an interpolation function as an intermediary between the limited measured color data and the full color correction table. This intermediary mathematical model enables accurate prediction of unmeasured color values based on the limited measured data, resolving the contradiction between measurement efficiency and interpolation accuracy.
Data Source
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AI summary
To generate a color correction table allowing accurate correction to be achieved in a mixed color area even with a small number of measured colors. A color correction table creation method for creating a color correction table for correcting a device-dependent value used as printing data to be input to a printing apparatus, including an output value acquisition step of acquiring, as an output value, a colorimetric result for a printed matter created by inputting a specific device-dependent value to the printing apparatus, an input value acquisition step of acquiring, as an input value for the color correction, a device-dependent value for a printed matter created by a reference printing apparatus to achieve the output value acquired, a correction value acquisition step of acquiring the specific device-dependent value as a correction value corresponding to the input value, and a creation step of creating the color correction table utilizing a relationship between the input value and the correction value.