Moving Sensor Surface for Single-Operation Fake Finger Discrimination
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Solution Overview
Problem
Existing fake-finger determination methods require multiple input operations and constant speed finger movements, leading to decreased user-friendliness and accuracy due to individual differences in fingerprint deformation.
Innovation Solution
A device with a moving sensor surface and imaging system that captures fingerprint images before and after movement, allowing for single-operation fake-finger determination by analyzing deformation differences between real and fake fingers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sweep-type sensor is used to capture fingerprint images, then fake-finger determination can be performed, but the user must slide the finger at constant speed in two directions, which deteriorates user-friendliness
Solution Approach 1:
Instead of moving the finger across a stationary sensor as in conventional sweep-type sensors, this invention inverts the approach by keeping the sensor movable and capturing images at different positions. The sensor moves relative to the finger to capture multiple fingerprint images at different locations, eliminating the need for the user to slide the finger and improving ease of operation while maintaining fake-finger determination capability
Solution Approach 2:
The fingerprint capture process is segmented into multiple discrete image captures at different sensor positions rather than requiring continuous finger sliding. The sensor captures images at multiple positions (e.g., front, middle, rear positions) independently, allowing the system to analyze deformation between these segmented captures without requiring the user to maintain constant sliding motion
2Reliability
If a sweep-type sensor is used requiring constant speed finger sliding, then fingerprint images can be captured for determination, but individual differences in finger deformation cause variance that deteriorates determination accuracy
Solution Approach 1:
The invention inverts the conventional approach by making the sensor movable rather than the finger. This eliminates the problem of individual differences in finger deformation during sliding, as the sensor-controlled movement provides consistent positioning and image capture at predetermined locations, thereby improving determination accuracy
Solution Approach 2:
The invention replaces the mechanical finger-sliding action with a controlled sensor movement system. Instead of relying on user-controlled finger motion, the sensor is moved in a controlled manner to capture images at specific positions, eliminating the variance caused by individual finger sliding mechanics and improving measurement precision
Data Source
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AI summary
Fingerprint images that are required for fake-finger determination can be acquired with a single input operation, and the user-friendliness and the determination accuracy of a fake-finger are improved. This device has moving means for moving a sensor surface, on which a finger as a determination object is placed, relatively to the finger, sensing means for acquiring fingerprint images of the finger before and after the sensor surface is moved, derivation means for obtaining a deformation level of the fingerprint before and after the sensor surface is moved based on two types of fingerprint images obtained by the sensing means, storage means for storing a deformation threshold related to the deformation level of the fingerprint to determine whether the finger on the sensor surface is a real finger or a fake-finger, and determination means for determining whether the finger placed on the sensor surface is a real finger or a fake-finger based on comparison results of the deformation level of the fingerprint obtained by the derivation means and the deformation threshold.