White Reference Plate Gray Balance Adjustment
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Solution Overview
Problem
Existing image reading apparatuses face challenges in accurately adjusting gray balance coefficients after parts such as light sources, lens blocks, or sensors are replaced, leading to variations in reading values due to differences in reading conditions, which complicates shading compensation and increases costs and complexity with the need for additional reference plates.
Innovation Solution
An image reading apparatus that reads a white reference plate under consistent conditions before and after shipment, adjusts the gray balance coefficient based on the obtained reading values, and performs shading compensation using the adjusted coefficient, eliminating the need for additional reference plates and ensuring accurate adjustments without requiring a reference chart during part replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a second reference plate is disposed separately from the white reference plate to adjust gray balance coefficient, then the gray balance can be adjusted after shipment, but the device complexity and cost increase due to additional reference plates
Solution Approach 1:
The white reference plate is designed to serve dual purposes: it functions as both the white reference plate for reading value measurement and as the second reference plate for gray balance coefficient adjustment. This multi-functionality eliminates the need for a separate second reference plate, reducing device complexity while maintaining the capability to adjust gray balance after shipment.
2Measurement precision
If a reference chart is used for gray balance adjustment, then accurate adjustment can be achieved, but the adjustment operation becomes time-consuming and complex
Solution Approach 1:
The invention extracts the essential function of the reference chart (providing known reflectance values for gray balance adjustment) and integrates it directly into the white reference plate by forming a light-shielding pattern on its surface. This eliminates the need for a separate reference chart, reducing adjustment time and operational complexity while maintaining adjustment accuracy.
3Adaptability or versatility
If different reading conditions are used before and after shipment, then adaptation to different environments is achieved, but reading value variations occur making adjustment difficult
Solution Approach 1:
The invention creates equipotential reading conditions by ensuring that the white reference plate is read under identical conditions both before and after shipment. The light-shielding pattern on the white reference plate provides consistent reference values that compensate for spectral characteristics variations, maintaining reading value consistency across different environments and time points.
Data Source
AI summary
An image reading apparatus incudes a white reference plate, a reading unit to read the white reference plate; and circuitry to: cause the reading unit to read the white reference plate under a first reading condition before shipment of the image reading apparatus to obtain a first reading value, cause the reading unit to read the white reference plate under a second reading condition same with the first reading condition after replacement of a part of the image reading apparatus after the shipment to obtain a second reading value, and adjust a gray balance coefficient based on the first reading value and the second reading value.