Color Measurement Device Position Correction via Calibration Chart
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Solution Overview
Problem
The increasing number of colors in color adjustment for printing units makes it impractical to manually accurately position a color measurement device, leading to errors due to installation inaccuracies and slip during conveyance, which existing methods fail to adequately address.
Innovation Solution
A color measurement device and method that uses a relative position calibration chart to derive the relative position relationship between the imaging and color measuring units, allowing for precise positioning of the color measuring unit to measure colors at the correct patch positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate imaging unit and color measuring unit are used, then color measurement capability is achieved, but positioning accuracy deteriorates due to installation errors and conveyance slip
Solution Approach 1:
A calibration chart serves as an intermediary element between the imaging unit and color measuring unit. The calibration chart includes calibration marks that are imaged by the imaging unit and then used to calculate the relative position relationship, which corrects the positioning of the color measuring unit. This mediator enables accurate positioning despite installation errors and conveyance slip.
Solution Approach 2:
The patent replaces mechanical positioning reliance with an optical-computational system. Instead of depending on precise mechanical installation and conveyance, the system uses the imaging unit to capture calibration marks, processes the image data computationally to determine relative positions, and applies correction algorithms to achieve accurate positioning of the color measuring unit.
2Device complexity
If design values are used for relative position relationship, then device complexity is reduced, but measurement accuracy deteriorates due to installation and dimensional errors
Solution Approach 1:
The system performs preliminary calibration by imaging the calibration chart and calculating the actual relative position relationship between the imaging unit and color measuring unit before color measurement. This preliminary action captures installation errors and dimensional inaccuracies, storing correction data that is applied during subsequent color measurements to maintain high accuracy.
3Device complexity
If manual positioning is used, then device complexity is minimized, but productivity deteriorates due to inability to handle increasing number of patches
Solution Approach 1:
The system implements self-service through automatic positioning. The imaging unit automatically captures the calibration chart, the computer automatically calculates the relative position relationship and corrects positions, and the color measuring unit automatically measures colors without manual intervention. This self-service capability enables efficient handling of color charts with increasing numbers of patches.
Solution Approach 2:
The system changes the operational mode from manual positioning to automated positioning based on calculated parameters. By deriving the relative position relationship from calibration mark coordinates and applying correction parameters, the system transforms the positioning process into an automated parameter-driven operation, significantly improving productivity.
Data Source
AI summary
A color measurement device acquires an image of a relative position calibration chart. The relative position calibration chart includes a calibration figure having a given calibration feature that has a position that is detectable along at least one of a first and a second direction. A color measurement of the relative position calibration chart is performed. Relative position relationship-related information is derived based on the calibration feature in the image of the relative position calibration chart and the calibration feature in the color measurement of the relative position calibration chart. A color of each patch of a number of patches of a color chart is measured at a position corresponding to one of the patches while correcting the position of the patch based on the position relationship-related information.