Calibration System Using Averaged Color Measurement Values
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Solution Overview
Problem
Conventional calibration methods for printing devices face challenges in achieving high-quality calibration when using color measurement devices of varying accuracy, as they require different patch patterns and can result in decreased accuracy due to in-plane unevenness and errors, especially with low-accuracy devices like scanners.
Innovation Solution
A calibration system that outputs a common patch sheet with patch patterns based on different gradation values for each color material, allowing selection of color measurement devices of varying accuracy, with a color adjustment unit that generates color correction information by averaging color measurement values and using higher-order polynomial interpolation, and performs weighting on color measurement values for accurate calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a color measurement device of low accuracy (e.g., scanner) is used for calibration, then the cost and accessibility are improved, but the measurement precision deteriorates leading to large errors in individual measurement values
Solution Approach 1:
The patent combines multiple scattered measurement values from the same patch pattern into a single averaged measurement value. This merging approach reduces the impact of large individual errors characteristic of low-accuracy devices like scanners, enabling acceptable calibration results even when using inexpensive measurement equipment.
Solution Approach 2:
The patent creates multiple copies of the same patch pattern on a single patch sheet. By printing the identical patch pattern multiple times across different positions, the system generates multiple measurement opportunities that can be averaged together, effectively compensating for the low accuracy of inexpensive measurement devices.
2Measurement precision
If a patch pattern with a greater number of patches distributed thereon is used to perform high-order polynomial interpolation, then the interpolation accuracy is improved, but the device complexity and calibration time increase
Solution Approach 1:
The patent merges multiple measurement values from patches with the same gradation value into a single averaged value before performing interpolation. This approach achieves accurate interpolation results without requiring an excessively large number of individual patches, thereby reducing patch pattern complexity while maintaining interpolation accuracy.
Solution Approach 2:
The patent uses a moderate number of patches distributed on the patch sheet, which is sufficient to perform reliable high-order polynomial interpolation without the excessive complexity that would result from using many more patches. This partial action approach achieves the necessary interpolation accuracy with manageable patch pattern design.
3Ease of operation
If a common patch sheet is used for all color measurement devices, then the ease of operation is improved, but the measurement precision deteriorates when using low-accuracy devices due to in-plane unevenness
Solution Approach 1:
The patent combines multiple measurement values obtained from different patch positions into averaged values for each gradation level. This merging process compensates for in-plane unevenness effects that would otherwise degrade measurement precision when using a common patch sheet with low-accuracy devices.
Solution Approach 2:
The patent distributes multiple patches of the same gradation value across different positions on the patch sheet. By treating each position as a separate measurement sample and averaging them, the system accounts for local variations (in-plane unevenness) while maintaining the simplicity of using a single common patch sheet for all devices.
Data Source
AI summary
A calibration system includes: an image formation unit that outputs a patch sheet having a plurality of patch patterns based on different gradation values for each color of color material that is used; a selection unit that receives an instruction to select a device from among a plurality of color measurement devices comprising a first color measurement device and a second color measurement device of a lower color measurement accuracy than that of the first color measurement device; a color measurement unit that receives data of a color measurement result for the patch sheet that is color-measured by the color measurement device selected by the selection instruction; a color measurement value determination unit that acquires color measurement values for each of the patch patterns on the basis of the color measurement result data received; and a color adjustment unit that generates color correction information of the image formation unit on the basis of the color measurement values acquired. In the system, the output patch sheet is common irrespective of the color measurement device selected by the selection instruction and, when the second color measurement device is selected by the selection instruction, the color measurement value determination unit acquires, by averaging a plurality of the color measurement result data that exist in the patch pattern, the color measurement values for each of the patch patterns.