Antispoofing Approach for Biometric Devices
Base paper: A New Antispoofing Approach for Biometric Devices
By P. Venkata Reddy, Ajay Kumar, Senior Member, IEEE, S. M. K. Rahman, and Tanvir Singh Mundra


Abstract:
The deployment of fingerprint sensors is increasingly becoming common and has now gained high user acceptance. However, fingerprint sensors are susceptible to spoofing using artificial materials or in worst case to the dismembered fingers. Fake/gummy fingerprints have shown to fool most commercial fingerprint systems. This paper proposes a new method of anti-spoofing using reliable liveness detection. The proposed method of liveness detection is based on the principle of pulse oximetry and involves the source of light originating from a probe at two wavelengths. The light is partly absorbed by haemoglobin, by amounts which differ depending on whether it is saturated with oxygen or deoxygenated haemoglobin. We then perform the computations for the absorption at two wavelengths to estimate the proportion of haemoglobin which is oxygenated. The computed percentage of oxygen in the blood, along with the heart pulse rate, determines the liveness of the enrolled biometric. Our experimental results demonstrate that the developed prototype can successfully thwart the spoof attacks (including those based on dismembered fingers).
Block Diagram:

The block diagram of the proposed anti-spoofing system using online liveness detection is shown in the above figure. The estimation of percentage of the oxygen saturated blood, in the presented finger, relies on the extraction and measurements from the transmitted signals.The pulse oximeter interacts with the finger while its being imaged. These sources are excited alternatively at high speed. The matched photo detector detects the reflected light and the corresponding photo current is converted into voltage by current to voltage converter. Channel separation mechanism separates the received frequencies, which synchronizes the sampling of signals with the excitation of corresponding emitters. The noise and unwanted high frequency components are removed The Liveness Factor is essentially the representation of the proportion of oxygen saturated blood.
Circuit diagram

References:
1) Liveness Detection for Biometric Systems Based on Papillary Lines
Martin Drahansky, Dana Lodrova
Brno University of Technology, Faculty of Information Technology
International Journal of Security and Its Applications
2) Liveness Detection in Fingerprint Recognition Systems
By Marie SandstrÄom.

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