Interleaved Biometric Spoof Detection Data Acquisition
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Solution Overview
Problem
Fingerprint sensors are susceptible to spoofing attacks due to their ability to image varying skin conditions and materials, making it difficult to distinguish between live and spoofed fingerprints effectively.
Innovation Solution
An electronic device with an array of finger sensing pixels and data acquisition circuitry that acquires biometric data and spoof detection data in an interleaved manner, using a biometric reading chain and spoof reading chain to determine the authenticity of a finger, including impedance sensing and processing to differentiate between live and spoofed fingers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If real-time gain and other adjustments are employed to image varying skin conditions, then the ability to acquire fingerprints under different skin conditions is improved, but susceptibility to spoofing attacks increases
Solution Approach 1:
The fingerprint sensor array is divided into multiple sub-arrays, with at least one sub-array dedicated to spoof detection and others dedicated to biometric data acquisition. This segmentation allows the system to simultaneously perform both functions using specialized circuits for each purpose, resolving the contradiction between adaptability to skin conditions and resistance to spoofing attacks.
2Reliability
If interleaved data acquisition is implemented, then security against spoofing is improved, but device complexity increases
Solution Approach 1:
The data acquisition circuitry merges spoof detection functionality with the existing biometric data acquisition circuitry by interleaving the acquisition processes. The same sensor array and reading chains are utilized for both spoof detection and biometric data collection, with time-division multiplexing to avoid requiring completely separate dedicated circuits, thus reducing the complexity increase.
3Reliability
If multiple sub-arrays are used for interleaved acquisition, then spoof detection capability is improved, but manufacturing complexity increases
Solution Approach 1:
Different regions (sub-arrays) of the fingerprint sensor are assigned different functional qualities - some regions are optimized for biometric data acquisition while others are optimized for spoof detection. This local differentiation allows each sub-array to be manufactured with specific characteristics suited to its purpose, while the overall array can be fabricated using standard semiconductor manufacturing processes.
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
Enhances security by making it more difficult to switch between live and spoofed fingers during biometric data acquisition, thereby increasing the reliability of fingerprint authentication.
Implementation Method 1
a fingerprint sensor including an array of impedance sensing elements for generating signals related to an object positioned adjacent thereto
Implementation Method 2
a synchronous demodulator for synchronously demodulating signals from the array of impedance sensing elements
Data Source
AI summary
An electronic device may include an array of finger sensing pixels and data acquisition circuitry coupled to the array. The data acquisition circuitry may be capable of acquiring finger biometric data from each sub-array of the array, and acquiring spoof detection data from at least one of the sub-arrays in an interleaved fashion with the finger biometric data.