Image Reading Device Invisible Mark Correction
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Solution Overview
Problem
Image reading devices face a reduction in the number of images that can be read per unit time due to frequent switching between background and correction surfaces, leading to decreased correction accuracy when temperature changes occur, as existing methods require calculating correction values only during significant temperature changes.
Innovation Solution
An image reading device with a background member featuring invisible marks that allows continuous detection of optical characteristic changes, enabling real-time correction of image characteristics without reducing the image reading frequency, using a detection unit and correction unit to determine and apply correction amounts based on the change in the interval between these marks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the background surface is switched to the correction surface on which the chart image is formed to calculate correction magnification, then the correction accuracy is improved, but the number of images to be read per unit time decreases
Solution Approach 1:
The patent introduces invisible marks as an intermediary element on the background surface. These marks serve as reference points that enable magnification correction calculations to be performed using the background surface itself, rather than requiring switching to a separate correction surface with chart images. This intermediary approach allows the background surface to dual-purpose: both for normal image reading and for correction calculations.
Solution Approach 2:
The background surface is given multi-functionality by incorporating invisible marks that enable it to serve both as a background for image reading and as a reference for magnification correction. Instead of requiring separate correction surfaces, the background surface itself becomes capable of providing correction data, thereby eliminating the need to switch surfaces and maintaining continuous image reading capability.
2Productivity
If the correction value of the magnification is calculated only when a temperature change equal to or greater than a predetermined value occurs, then the reading frequency is maintained, but the correction accuracy decreases when temperature changes are small
Solution Approach 1:
The patent implements continuous feedback by periodically detecting the positions of invisible marks and calculating magnification values at regular intervals regardless of temperature change magnitude. This feedback mechanism ensures that correction data is continuously updated and stored, allowing the system to maintain high correction accuracy by selecting appropriate correction values based on current conditions rather than relying on threshold-based triggering.
Solution Approach 2:
The system performs preliminary correction calculations by detecting invisible marks and storing magnification values in advance at regular intervals. This preliminary action ensures that correction data is ready and available before actual temperature changes occur, allowing the system to quickly apply appropriate corrections without waiting for temperature thresholds to be met, thereby maintaining both high reading frequency and correction accuracy.
Data Source
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AI summary
An image reading device includes a reading unit (20), a background member (30), a detection unit (40), and a correction unit (50). The reading unit includes a light source (21) to emit light to a passage area through which an object passes and an imaging device (22) to capture reflected light of the light to generate a visible image and an invisible image. The background member is disposed opposite the light source across the passage area. The detection unit detects a change in an image characteristic due to a change in an optical characteristic of the reading unit, in invisible images obtained by capturing of invisible marks on the background member. The correction unit determines a correction amount of an image characteristic to be used for correcting an image of the object, based on the change in the image characteristic, and corrects the image characteristic based on the correction amount.