Image Reading Apparatus Shading Correction via Dynamic Reference Plate Timing
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Solution Overview
Problem
The existing image reading apparatuses face challenges in performing shading correction with high accuracy due to temperature changes in the reading unit, leading to increased costs from the requirement of temperature sensors and memory for storing shading correction values.
Innovation Solution
The image reading apparatus includes a movable reading unit that adjusts the time interval for reading a white reference plate based on the number of processes performed and the reading period, generating a shading correction value each time to maintain accurate shading correction without the need for a temperature sensor, thereby reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor and memory are added to detect and store shading correction values according to temperature changes, then shading correction accuracy is improved, but device cost increases
Solution Approach 1:
The reading unit itself is used to detect temperature changes by monitoring its own reading results. When the reading result deviates from the reference value, the system automatically performs self-correction by updating the shading correction value stored in the memory, without requiring external temperature sensors or complex control systems
Solution Approach 2:
The system establishes a feedback mechanism where the reading result is continuously monitored and compared against reference values. When deviations occur indicating temperature changes, the system automatically adjusts the shading correction value in response, creating a closed-loop control system that maintains accuracy without additional hardware
2Measurement precision
If the reading unit frequently reads the white reference plate to maintain accurate shading correction, then shading correction accuracy is improved, but productivity decreases due to unnecessary processes
Solution Approach 1:
The system dynamically changes the timing parameter for reading the white reference plate based on actual temperature changes. Instead of fixed frequent readings, the system adjusts the reading interval according to whether temperature deviations are detected, performing readings only when necessary to maintain accuracy while improving overall productivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for high-accuracy shading correction while minimizing the increase in the apparatus's cost and improving productivity by reducing unnecessary processes.
Implementation Method 1
The reading unit also includes a reading sensor to receive reflected light from the reading surface and photoelectrically converts the received reflected light to generate an electric signal representing the image of the original
Data Source
AI summary
An image reading apparatus includes a stacking unit, a conveyance unit to convey stacked sheets, a reading unit, a white reference plate provided in a second position, and a processor. The reading unit is movable and, at a first position, reads a conveyed sheet image to obtain image data and, at the second position, reads the white reference plate. The processor generates, based on a plate reading result, a shading correction value and corrects the image data using the shading correction value. Based on whether the number of times in which reading the white reference plate has been performed is less than a predetermined number of times, the reading unit changes a time interval in a reading period that is from a first timing to a second timing. The processor generates, each time the white reference plate is read, the shading correction value based on the plate reading results.