Image Reader Reference Scans for Foreign Matter-Resistant Shading
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Solution Overview
Problem
Existing image reading apparatuses face issues with accurate shading correction due to foreign matter on white reference members, leading to uneven luminance and white streaks in the reading image, and existing methods for addressing this are inadequate.
Innovation Solution
The apparatus employs a reader that moves from outside to inside a region to read a reference member twice, using the first and second reading results for shading correction, and interpolates correction data for abnormal pixels to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If shading correction is performed using reading data from a white reference member with foreign matter, then shading correction data is generated, but the reading image exhibits abnormal values and white streaks at the foreign matter position
Solution Approach 1:
The patent performs preliminary actions by reading the white reference member multiple times before actual image reading to detect and identify foreign matter positions. The reader moves to different positions in the sub-scanning direction and reads the reference member at each position, allowing abnormal values to be detected before they affect the final reading image.
Solution Approach 2:
The patent extracts harmful information by identifying positions of abnormal values caused by foreign matter and excluding these positions from the shading correction data. The processor determines abnormal values by comparing reading data across multiple positions and removes or corrects these abnormal values to prevent white streaks in the final image.
2Reliability
If the reader reads the white reference member multiple times at different positions, then foreign matter positions can be identified, but the processing time and complexity increase
Solution Approach 1:
The patent segments the white reference member reading process into multiple discrete positions in the sub-scanning direction. The reader moves to specific positions (first position, second position, third position) and performs reading operations at each segment. This segmentation allows systematic detection of foreign matter while maintaining manageable processing complexity through structured multi-position reading.
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 method enhances shading correction accuracy by reducing the influence of foreign matter, ensuring uniform luminance and preventing white streaks in the reading image.
Implementation Method 1
a reader configured to read one of an original or the reference member
Data Source
AI summary
Disclosed is an image reading apparatus including a reference member, a reader configured to read one of an original or the reference member, a mover configured to move the reader to a first region in which the original is read and a second region in which the reference member is read in a conveying direction of the original, and at least one processor configured to perform shading correction, wherein the at least one processor is configured to control the reader to move from outside of the second region to inside of the second region in the conveying direction to perform a first reading operation of reading the reference member within the second region.