Shading Data Correction for Image Scanning Apparatus
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Solution Overview
Problem
Conventional image scanning apparatuses face image distortion due to pollutants like paper dust or foreign matter attached to the shading reference, which degrades image quality, especially in sheet-fed systems where the shading reference is externally exposed.
Innovation Solution
Acquire shading data during manufacturing when the white reference is clean, and compare it with data collected during use to identify and correct for failed pixels, calculating a standard average shading value to set new shading data for contaminated pixels, thereby preventing distortion such as white lines in the image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shading correction is performed using a white reference or shading reference during operation, then shading distortion can be corrected, but image quality deteriorates when pollutants like paper dust attach to the reference
Solution Approach 1:
The patent applies preliminary action by acquiring shading data during the manufacturing process when the white reference and shading reference are guaranteed to be clean, storing this data for future use. This prevents the problem of pollutant contamination that occurs when references are exposed during operation, thereby maintaining both reliable shading correction and high image quality throughout the device's lifetime.
2Ease of operation
If the shading reference is externally exposed for easy access, then ease of operation improves, but susceptibility to pollutant contamination increases
Solution Approach 1:
The patent eliminates the need for external exposure of the shading reference by performing shading data acquisition during manufacturing when the reference is protected and clean. The shading reference can then be positioned internally or in a protected location, reducing its exposure to pollutants while maintaining ease of operation through automated processes.
3Manufacturing precision
If shading data is acquired during manufacturing when clean, then image quality is maintained, but the system cannot adapt to changes in lighting conditions during operation
Solution Approach 1:
The patent creates a copy of the ideal shading data during manufacturing when conditions are optimal and无污染. This copied data is then used during operation to correct shading distortions. The system compares current shading measurements against the stored reference copy, allowing it to maintain image quality while adapting to varying lighting conditions through computational correction rather than physical reference exposure.
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 effectively eliminates image distortion caused by pollutants, improving the overall performance of the image scanning apparatus by ensuring accurate shading correction and maintaining image quality.
Implementation Method 1
An image sensor such as a charge coupled device (CCD) or a contact image sensor (CIS) produces an electrical signal proportional to the amount of light reflected by the original document
Implementation Method 2
a color CIS detects the amount of each of red, green, and blue (RGB) light beams alternately irradiated from RGB LEDs and reflected from an original document
Data Source
AI summary
An image scanning apparatus and method are provided in which shading data of the image scanning apparatus is acquired when manufacturing the image scanning apparatus, which is when a white reference or the shading data is cleanest. An original document is scanned using the shading data acquired when manufacturing the image scanning apparatus and shading data of non-contaminated regions of a white reference or shading reference, thereby eliminating distortion such as white lines in an image caused by pollutants stuck to the shading reference or the white reference and improving the performance of the image scanning apparatus. The apparatus and method includes acquiring the shading data when manufacturing the image scanning apparatus and storing the shading data in a memory, and comparing the shading data acquired when manufacturing the image scanning apparatus with shading data acquired when using the image scanning apparatus and, based on the result of the comparison, processing the image of the original document.