Scanner Light Source Array Shading Correction
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Solution Overview
Problem
Image scanning apparatuses face challenges in correcting scanned images due to variations in light quantity and abnormality detection of light emitting elements, leading to issues like black streaks and reduced image quality.
Innovation Solution
An image scanning apparatus with a light quantity information acquiring unit, correction unit, and abnormality detecting unit that reacquires shading data when abnormalities are detected, allowing for real-time correction of scanned images by adjusting light quantity information based on a reference member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the image scanning unit uses an array-type light source with multiple light emitting elements, then the scanning speed and productivity are improved, but the reliability deteriorates due to potential abnormalities in individual light emitting elements causing black streaks and image quality degradation
Solution Approach 1:
The system performs preliminary abnormality detection on light emitting elements before they cause image quality degradation. The abnormality detecting unit continuously monitors the light quantity from each element, and when an abnormality is detected, the system proactively reacquires shading data to prevent black streaks and maintain image quality, rather than waiting for problems to manifest in the scanned images
Solution Approach 2:
The system implements a feedback mechanism where the abnormality detecting unit provides real-time information about the state of light emitting elements to the correction unit. When abnormalities are detected, the system automatically reacquires shading data and updates the correction parameters, creating a closed-loop control system that maintains image quality despite variations in light source performance
2Reliability
If the system continuously monitors light emitting elements for abnormalities, then the reliability is improved, but the device complexity increases due to additional detection and correction mechanisms
Solution Approach 1:
The light receiving portion serves multiple functions: it is used for normal image scanning and also for abnormality detection of light emitting elements. The same hardware components (light source array, light receiving portion, and processing unit) are utilized for both shading correction and abnormality detection, eliminating the need for separate dedicated detection hardware and reducing overall system complexity
Solution Approach 2:
The system uses its own scanning infrastructure to perform self-diagnosis. The light receiving portion that normally captures document images is also used to detect abnormalities in the light emitting elements by scanning a reference member. This self-service approach allows the system to monitor its own health without requiring external diagnostic equipment
3Manufacturing precision
If the system reacquires shading data when abnormalities are detected, then the manufacturing precision is improved by maintaining image quality, but the loss of time increases due to additional acquisition and correction processes
Solution Approach 1:
The system performs preliminary abnormality detection continuously during normal operation, so when an abnormality is detected, the reacquisition of shading data can be initiated immediately as a preventive measure. This preliminary detection approach minimizes the time loss by catching abnormalities early, before they cause visible image degradation that would require re-scanning of documents
Solution Approach 2:
The system dynamically changes the operational parameters of the light source by adjusting the drive current to compensate for abnormalities. When a light emitting element shows signs of degradation, the system can increase the current to other elements or adjust the overall illumination levels to maintain consistent image quality without requiring full reacquisition of shading data, thereby reducing time loss
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 solution ensures continuous and high-quality image scanning by preventing downtime and improving shading correction accuracy, even when light emitting elements fail or experience reduced brightness, maintaining consistent image output.
Implementation Method 1
a light receiving portion receiving light emitted from the plural light emitting elements and reflected on a document
Data Source
AI summary
An image scanning apparatus includes: an image scanning unit that includes plural light emitting elements and a light receiving portion receiving light emitted from the light emitting elements and reflected on a document and scans an image on the document; a light quantity information acquiring unit that acquires light quantity information on the quantity of light received by the light receiving portion while causing the light emitting elements to irradiate a reference member with light; a correction unit that corrects the scanned image, based on the light quantity information; and an abnormality detecting unit that detects abnormality of the light emitting elements. If the abnormality detecting unit detects the abnormality, the light quantity information acquiring unit acquires new light quantity information while causing the light emitting elements to irradiate the reference member with light and the correction unit corrects the scanned image, based on the new light quantity information.