Biometric Liveness Detection via Capacitive and PPG Sensor Fusion
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Solution Overview
Problem
Fingerprint scanners are vulnerable to spoofing attacks, as they can be easily fooled by fake fingerprints, which compromises their security and accuracy in authentication processes.
Innovation Solution
Integration of a capacitance sensor and a pulse sensor with a microprocessor in biometric scanner devices to differentiate between real and fake fingers by measuring capacitance and pulse data, generating a threshold value, and analyzing fingerprint patterns for authentication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fingerprint scanners are used, then the authentication process is simple and fast, but the system is vulnerable to spoofing attacks and has low security
Solution Approach 1:
The patent combines multiple sensing modalities (capacitive sensing, photoplethysmography, and fingerprint scanning) into a single integrated sensor device. This merging allows the system to simultaneously capture electrical properties, blood flow patterns, and fingerprint characteristics, thereby improving reliability and security without requiring multiple separate devices
Solution Approach 2:
The sensor device performs multiple functions: it acts as a capacitive touch sensor for presence detection, a PPG sensor for liveness verification through blood flow detection, and a fingerprint scanner for identity verification. This multi-functionality enables comprehensive authentication while maintaining a single-device form factor
2Reliability
If fingerprint scanners are enhanced with additional sensors, then the anti-spoofing capability is improved, but the device complexity increases
Solution Approach 1:
The patent integrates capacitive sensing elements, PPG sensors, and fingerprint scanning functionality into a unified sensor array. By merging these sensing modalities into a single device structure with shared processing circuitry, the system achieves enhanced anti-spoofing capability without proportionally increasing overall device complexity
Solution Approach 2:
The sensor device autonomously processes multiple types of biometric data simultaneously, using its own integrated processors to analyze capacitive patterns, PPG signals, and fingerprint images. This self-service capability reduces the need for external processing systems, thereby limiting the increase in device complexity
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
The solution effectively enhances the security of fingerprint scanners by accurately distinguishing between real and fake fingers, achieving a high success rate of 99.6% in detecting human fingers and 100% in identifying artificial fingers, thereby preventing unauthorized access.
Implementation Method 1
the add-on part may include a capacitance sensor configured to measure a capacitance of an object
Implementation Method 2
The anti-spoofing method may include measuring, with an add-on part comprising a photoplethysmography (PPG) sensor and a capacitance sensor, PPG data and capacitance data of an object
Data Source
AI summary
A method may include measuring, photoplethysmography (PPG) data and capacitance data of an object. The method may also include, with the PPG data and the capacitance data, detecting, by a microprocessor, positive peaks of the data by comparing successive measurements. The method may further include finding, by the microprocessor, a maximum peak value of the detected positive peaks, and generating, by the microprocessor, a threshold value based on detected positive peaks. If the maximum peak value is greater than the threshold value, analyze, by the microprocessor, a fingerprint of the object. The method may also include determining, by the microprocessor, based on the PPG data, the capacitance data and the fingerprint of the object, at least one of if the object is authorized or unauthorized, and if the object is a human being or not a human being.