Fingerprint Image Inversion for Fake Finger Detection
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Solution Overview
Problem
Current fingerprint authentication systems face challenges in accurately distinguishing between real and fake fingers, particularly when a fake finger is created by reversing the concavity and convexity of a real fingerprint, making it difficult to determine authenticity.
Innovation Solution
The implementation of a software-based fake finger determination device that analyzes the ridge and valley line widths in fingerprint images, reversing the typical characteristics of a fake finger to differentiate it from a real finger, without requiring additional hardware, by using a computer with image input, region splitting, direction deciding, line width calculation, and line width relation determination means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spectral characteristics are measured upon fingerprint authentication, then authentication can be performed, but it becomes difficult to determine whether the finger is fake since the spectral characteristics of the fake finger surface and the real finger surface will basically be the same
Solution Approach 1:
The patent applies inversion by reversing the typical fingerprint image to identify fake fingers. Instead of analyzing the fingerprint as captured, the system reverses the image and then analyzes ridge and valley line widths. This inversion transforms the characteristic pattern of fake fingers (where ridges appear as valleys and valleys appear as ridges) into a form where the abnormal line width ratios become detectable, allowing the system to distinguish fake from real fingers despite similar spectral characteristics.
2Ease of manufacture
If a thin film is pressed on the finger surface to create a forged fingerprint, then a fake fingerprint can be created, but the concavity and convexity are reversed making detection difficult
Solution Approach 1:
The patent directly addresses this by inverting the fingerprint image before analysis. When a thin film is pressed on the finger, it creates a reversed pattern where ridges become valleys and valleys become ridges. By reversing the image, the system restores the apparent orientation but preserves the abnormal line width characteristics, making the fake fingerprint detectable through its unusual ridge and valley line width ratios.
3Measurement precision
If additional hardware is added to detect fake fingers, then detection capability may be improved, but device complexity increases
Solution Approach 1:
The patent replaces potential mechanical or hardware-based detection methods with a software-based image processing approach. Instead of adding complex hardware sensors or devices to detect fake fingers, the system uses software to reverse the fingerprint image and analyze line width characteristics. This substitution of mechanical/system complexity with software processing achieves accurate fake finger detection while maintaining simplicity of the overall device.
Data Source
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AI summary
Provided is fake finger determination technology capable of improving the determination accuracy of a fake finger. A fake finger determination device comprises acquisition means for acquiring line width information related to a line width of a ridge or a line width of a valley line of a finger as a determination object, and determination means for determining whether or not the finger as the determination object is a real finger or a fake finger based on the line width information.