Image Reading Device Dual-Light Scanning for Thin Document Detection
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Solution Overview
Problem
Image reading devices face difficulties in accurately detecting the size of standard size documents, especially thin documents, due to the likelihood of shadows on the document edges, which can lead to incorrect size detection.
Innovation Solution
The image reading device employs a reading sensor with a light source that performs first scanning with a lower light quantity for document size detection and subsequent second scanning with a higher light quantity for accurate reading, using single-side irradiation for thin documents to emphasize shadows and double-side irradiation for thicker documents to cancel surface irregularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single scanning with standard light quantity is performed, then the reading speed is maintained, but the document size detection accuracy deteriorates for thin documents
Solution Approach 1:
The scanning process is divided into two separate scanning operations: a first scanning at a first light quantity for document size detection, and a second scanning at a second light quantity for actual reading. This segmentation allows each scanning to be optimized for its specific purpose, resolving the contradiction between detection accuracy and reading speed.
Solution Approach 2:
The first scanning is performed as a preliminary action before the second scanning. By detecting document size first using light that emphasizes shadows, the system can then adjust subsequent reading parameters, ensuring accurate detection without compromising overall reading efficiency.
2Measurement precision
If high light quantity is used for scanning, then the reading accuracy is improved, but the power consumption increases
Solution Approach 1:
The system applies partial action by using two different light quantities appropriately: a lower first light quantity for size detection and a higher second light quantity only when needed for actual reading. This avoids continuous high power consumption while maintaining reading accuracy when required.
Solution Approach 2:
The light quantity parameter is changed between two scanning operations. The system dynamically adjusts the light quantity based on the scanning purpose, using lower light quantity for detection and higher light quantity for reading, thereby optimizing power consumption while maintaining accuracy.
3Use of energy by moving object
If standard light quantity is used for all documents, then the power consumption is minimized, but the detection accuracy for thin documents deteriorates
Solution Approach 1:
The system applies local quality by using different light quantities for different scanning purposes and different document types. The first light quantity is specifically optimized for thin document detection, while the second light quantity is optimized for general reading, ensuring both energy efficiency and detection accuracy where needed.
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 approach enhances the accuracy of document size detection and reading, particularly for thin documents, by minimizing power consumption and ensuring precise detection of document dimensions and textures.
Implementation Method 1
when reading a standard size document, the document size and the image are read in one scan. However, in the case of thin documents, shadows are less likely to appear on the edge of the document, and there is a problem that the image reading device may not be able to correctly detect the size of a standard size document.
Data Source
AI summary
A document platen on which a document is placed; and a reading sensor having a light source for irradiating the document with light, are provided, and the reading sensor performs first scanning for irradiating the document with light at a first light quantity, and then performs second scanning for irradiating the document with light at a second light quantity greater than the first light quantity.