Color Matching Correction Using Adjacent Gray Prediction
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Solution Overview
Problem
Existing color matching techniques for printed materials impose a heavy load on users for frequent color measurements and struggle with accurate correction due to large changes in color mixing characteristics over time.
Innovation Solution
An image processing apparatus and method that accurately corrects color mixtures by using a prediction model created from adjacent gray values, reducing the need for frequent color measurements and improving correction accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If color measurement is performed frequently to ensure accurate color matching, then color matching accuracy is improved, but user burden and measurement load increase
Solution Approach 1:
The system performs preliminary color measurement and creates a prediction model during an initial calibration phase. This pre-acquired data is then used to predict colorimetric values during subsequent print jobs, eliminating the need for frequent repeated measurements while maintaining accuracy.
Solution Approach 2:
Instead of repeatedly measuring actual colorimetric values during each print job, the system creates and uses a prediction model that copies the relationship between dot area ratios and colorimetric values from the calibration phase. This model is applied to predict values for new print conditions without requiring physical measurement.
2Manufacturing precision
If color measurement is performed frequently to capture current color state, then correction accuracy is improved, but measurement time and frequency increase
Solution Approach 1:
The calibration process is performed preliminarily to establish the prediction model before actual print jobs begin. This upfront investment of time creates a reusable model that provides accurate corrections during subsequent operations without requiring repeated measurement time.
Solution Approach 2:
Instead of continuous or frequent periodic measurements during each print job, the system uses a single calibration phase followed by model-based prediction. The measurement action becomes periodic at the calibration stage rather than continuous during operation, reducing total measurement time while maintaining correction accuracy.
3Measurement precision
If prediction model uses adjacent gray values to predict colorimetric values, then correction accuracy is improved despite color mixing changes, but model complexity increases
Solution Approach 1:
The prediction model uses dot area ratios as the key parameter to predict colorimetric values. By focusing on this fundamental parameter and its relationship to color output, the model can adapt to color mixing changes without requiring complex multi-parameter calculations, maintaining accuracy while controlling complexity.
Data Source
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AI summary
An image processing apparatus (1) performs color matching of colors acquired in two different states and having an identical target gradation value, the two different states including a first state and a second state. The image processing apparatus includes a first acquisition unit (13) configured to acquire a first colorimetric value of a target color mixture from a chart printed out from an image forming apparatus, based on one or more first gradation values, in the first state, the first colorimetric value corresponding to each of the one or more first gradation values. The image processing apparatus includes a second acquisition unit (12) configured to acquire a second colorimetric value of an adjacent color mixture, for a second gradation value adjacent to at least one first gradation value among the one or more first gradation values, from the chart printed out from the image forming apparatus in the first state and acquire a second colorimetric value of an adjacent color mixture, for a second gradation value adjacent to a remaining first gradation value other than the at least one first gradation value among the one or more first gradation values, from a chart printed out from the image forming apparatus in the second state, the second state being a state that occurs chronologically after the first state. The image processing apparatus includes a third acquisition unit (15) configured to acquire a third colorimetric value of a pre-correction color mixture from a chart printed out from the image forming apparatus, based on each of the one or more first gradation values, in the second state, the third colorimetric value corresponding to each of the one or more first gradation values. The image processing apparatus includes a first calculation unit (15) configured to add a difference between the first colorimetric value and the second colorimetric value corresponding to the first colorimetric value to the third colorimetric value corresponding to the first colorimetric value and calculate a predicted colorimetric value of the target color mixture. The image processing apparatus includes a first determination unit (15) configured to determine whether a color difference between the predicted colorimetric value and the first colorimetric value corresponding to the predicted colorimetric value is less than or equal to a first threshold. The image processing apparatus includes a fourth acquisition unit (15) configured to acquire, as a correction value, the second gradation value corresponding to the second colorimetric value from which the predicted colorimetric value corresponding to the color difference is calculated, in response to the color difference being less than or equal to the first threshold. The image processing apparatus includes a correction unit (18) configured to correct a corresponding one of the one or more first gradation values by using the correction value such that a colorimetric value of the pre-correction color mixture becomes equal to a colorimetric value of the target color mixture.