ID Card Detection via Corner Roundness Analysis
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Solution Overview
Problem
Existing medium conveying apparatuses face challenges in accurately distinguishing between ID cards and multi-feed conditions due to similar ultrasonic wave reception levels, leading to potential misclassification of ID cards as multi-feed, and struggle to classify images from ID cards and other media effectively.
Innovation Solution
A medium conveying apparatus that includes a conveying roller, an imaging device to generate input images, and a processor to extract edge pixels, detect the degree of roundness at the corners of the medium, and determine whether the conveyed medium is an ID card based on this analysis, thereby controlling the conveying process or outputting the determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultrasonic wave reception level is used to detect multi-feed, then multi-feed detection capability is improved, but ID card misclassification occurs because ID cards produce similar ultrasonic signals
Solution Approach 1:
The patent segments the detection process into two independent stages: first detecting multi-feed using ultrasonic waves, then determining ID card presence using image processing. This segmentation allows each detection method to operate independently without interference, resolving the contradiction between multi-feed detection reliability and medium classification precision
Solution Approach 2:
The patent introduces an intermediary image processing step that acts as a mediator between ultrasonic multi-feed detection and final medium classification. The image processing unit captures visual characteristics of the medium and provides additional information to distinguish ID cards from actual multi-feed cases, where ultrasonic signals alone are insufficient
2Measurement precision
If image processing is added to determine ID cards, then medium classification accuracy is improved, but device complexity increases
Solution Approach 1:
The patent makes the imaging device serve multiple functions: it captures images for ID card determination, monitors medium conveyance status, and provides visual feedback for multi-feed detection. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in device complexity while improving classification accuracy
Solution Approach 2:
The image processing unit utilizes the existing imaging infrastructure of the scanner to perform ID card determination, rather than requiring a completely separate detection system. The system uses its own imaging resources to solve the classification problem, minimizing additional complexity
Data Source
AI summary
A medium conveying apparatus includes a conveying roller to convey a medium, an imaging device to generate an input image acquired by imaging the conveyed medium, and a processor to extract edge pixels from the input image, detect a degree of roundness at a corner of the medium in the input image based on the edge pixels, determine whether the conveyed medium is an ID card based on the degree of roundness, and control the conveying roller based on a result of the determination or outputs the result of the determination.