Image Reading Apparatus Foreign Object Position Detection
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Solution Overview
Problem
Image reading apparatuses face challenges in accurately determining the position of foreign objects, such as dust or paper powder, which cause vertical stripe noise in document images, especially when these objects are on the image capturing device or a reference plate, making it difficult to correct the images effectively.
Innovation Solution
The apparatus includes a first unit with an image capturing device, a second unit with a reference member, and a conveyance mechanism to capture images of both the document and the reference member, allowing for the determination of whether a foreign object exists on the image capturing device or the reference member side by comparing images before and after document conveyance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a captured image of a plain reference plate is used to determine foreign object presence, then measurement precision is improved, but difficulty of detecting and measuring increases
Solution Approach 1:
The patent divides the imaging space into two distinct units: a first unit with an image capturing device and a second unit with a reference member. By capturing images separately from these two units and comparing them, the system segments the detection process to identify whether foreign objects are on the image capturing device side or reference member side, thereby resolving the difficulty of position determination while maintaining high detection accuracy
Solution Approach 2:
The reference member serves as an intermediary element between the image capturing device and the document. By capturing images of the reference member from both units and comparing them, the system uses this intermediary to indirectly determine foreign object positions without directly observing the foreign objects themselves, thus improving measurement precision while managing detection difficulty
2Adaptability or versatility
If various characters and pictures are printed on documents, then adaptability is improved, but measurement precision deteriorates
Solution Approach 1:
The patent performs preliminary image capture of the reference member from both the first unit and second unit before document imaging. This preliminary action establishes baseline reference images that can be used to detect foreign objects regardless of what is subsequently printed on or placed on the document, thereby maintaining measurement precision while accommodating various document types
Solution Approach 2:
Instead of trying to detect foreign objects directly on documents with various printed content, the patent inverts the approach by capturing images of the reference member from both imaging units and comparing them. This indirect method allows foreign object detection to proceed independently of document content, maintaining both adaptability to different documents and precision in foreign object detection
Data Source
AI summary
Provided are an image reading apparatus and the like for accurately determining the position where an extraneous substance exists. An image reading apparatus comprises: a first unit having an image capture section for capturing a first image and a second image; a second unit having a reference member placed at a position opposed to the image capture section; a conveying mechanism for conveying an original between the first unit and the second unit such that a front end of the original is in contact with one of the first unit and the second unit; an extraneous substance determination unit that determines whether an extraneous substance is included in the first image and the second image; and a position determination unit that, if an extraneous substance is included in the first image, determines whether the position where the extraneous substance exists is on the first unit side or on the second unit side, on the basis of whether the extraneous substance is included in an area of the second image corresponding to an area of the first image in which the extraneous substance is included. The first image is an image obtained by capturing an image of the reference member, while the second image is an image obtained by capturing an image of the reference member after the first image is captured and further the original is conveyed thereafter.