Fingerprint Sensor Spoof Detection via Impedance and Polarization
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Solution Overview
Problem
Current fingerprint sensors in electronic devices often require full fingerprint matching for unlocking, which is time-consuming and power-intensive, and do not effectively differentiate between live and spoof fingers, compromising security and convenience.
Innovation Solution
An electronic device with a finger biometric sensor and processor that switches between locked and unlocked modes based on spoof detection data, allowing for quicker unlocking with live finger detection using complex impedance, light polarization, or spatial alignment data, and performs biometric matching for enhanced security and convenience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full fingerprint matching is performed for unlocking, then security is improved, but unlocking time and power consumption increase
Solution Approach 1:
The authentication process is divided into two segments: a quick spoof detection phase that checks for live finger characteristics (complex impedance, light polarization, spatial alignment), and a full fingerprint matching phase. This segmentation allows the system to quickly reject obvious spoof attempts without performing complete fingerprint matching, thereby reducing unlocking time while maintaining security.
Solution Approach 2:
The system performs only partial authentication actions (spoof detection checks) when a finger is detected, rather than immediately performing the complete fingerprint matching process. This partial action approach enables rapid preliminary verification that can quickly eliminate spoof attempts, reducing both time and power consumption while maintaining security through the ability to perform full matching when needed.
2Reliability
If full fingerprint matching is performed for unlocking, then security is improved, but power consumption increases
Solution Approach 1:
The power-intensive full fingerprint matching process is segmented and separated from the initial finger detection phase. The system performs low-power spoof detection checks first (analyzing complex impedance, light polarization, or spatial alignment properties), and only proceeds to full fingerprint matching when the spoof detection is passed. This segmentation significantly reduces average power consumption by avoiding complete matching for spoof attempts.
Solution Approach 2:
The system performs only partial authentication (spoof detection) rather than the complete power-intensive fingerprint matching process for every finger detection event. This partial action approach minimizes power consumption by performing minimal necessary checks to identify and reject spoof attempts, reserving the full matching process only for genuine authentication cases.
3Adaptability or versatility
If traditional fingerprint sensors are used, then authentication capability is provided, but ability to differentiate live and spoof fingers is insufficient
Solution Approach 1:
The patent merges multiple sensing modalities into a single authentication system: traditional fingerprint sensing combined with spoof detection capabilities using complex impedance sensing, light polarization detection, or spatial alignment analysis. This merging allows the system to maintain full authentication capability while simultaneously gaining robust spoof detection capability, as the multiple sensing approaches work together to distinguish live fingers from spoofs.
Solution Approach 2:
The fingerprint sensor system is designed with multi-functionality, serving both traditional authentication purposes and spoof detection purposes. By incorporating additional sensing capabilities (impedance, polarization, spatial alignment) that serve dual purposes, the system achieves versatility in authentication while simultaneously improving reliability in distinguishing live fingers from spoof attempts.
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
Enables rapid and secure unlocking of electronic devices by distinguishing live fingers from spoofs, reducing power consumption and improving access convenience compared to traditional full fingerprint matching methods.
Implementation Method 1
acquire spoof detection data based upon an object being placed adjacent the finger biometric sensor
Implementation Method 2
acquire light polarization data, and perform the spoof detection based upon acquired light polarization data
Implementation Method 3
acquire spatial alignment data, and perform the spoof detection based upon acquired spatial alignment data
Data Source
AI summary
An electronic device may include a finger biometric sensor and a processor being switchable between a user-interface locked mode and a user-interface unlocked mode. The processor may cooperate with the finger biometric sensor to acquire spoof detection data based upon an object being placed adjacent the finger biometric sensor, and determine whether the acquired spoof detection data is representative of a live finger. The processor may also switch from the user-interface locked mode to the user-interface unlocked mode when the acquired spoof detection data is representative of a live finger, and cooperate with the finger biometric sensor to acquire biometric matching data. The processor may further perform finger matching based upon the acquired biometric matching data and stored biometric enrollment data.