Toward Advanced Security Fingerprint Biometrics Using Super-Resolution Terahertz Microscopy

We propose a high spatial resolution fingerprint scanning method that utilizes subterahertz (THz) waves to image the finger skin surface and subsurface. The fingerprint is a biomarker widely used as an identifier in security applications. However, current popular fingerprint scanners mostly detect skin surface undulation and hence are vulnerable to spoofing attacks. The proposed approach leverages THz wave penetration into the multilayered skin structure to provide a unique spectral response and enable higher security fingerprint scanning. By implementing an imaging system that scans the fingerprint using a tightly focused THz beam, we present measurement results of an in-vivo finger specimen in the 330-500 GHz range. High-resolution fingerprint images and THz frequency responses are obtained. Besides, two spoof samples are fabricated using latex for comparison. The measurement results show a noticeable discrepancy compared with real skin, which can be used to distinguish fake fingerprints (spoofs).