Towards Protected and Cancelable Multi-Spectral Face Templates Using Feature Fusion and Kernalized Hashing

Abstract

Multi-spectral imaging has been explored to handle a set of deficiencies found in traditional imaging that capture the images only in visible spectrum (VIS) or Near-Infra Red (NIR) spectrum. The promising performance obtained in the experimental works indicates the use-case in real-life biometric systems. As biometric systems should also consider protecting biometric templates, it is required to have an efficient template protection scheme for multi-spectral biometric systems to avoid the leakage of biometric data and subsequent linkability issues. In this work, we propose a new template protection scheme for multi-spectral biometric systems through the use of biometric information across different spectra to provide protected templates. Through the proposed approach of kernalized hashing, we can reach a fully unlinkable template protection scheme that works across all spectra in a multi-spectral system with a comparable performance to unprotected system. Further, we propose a template level fusion across all the spectral bands to improve the performance of the multi-spectral biometric system with integrated template protection. Through the use of a relatively large sized multispectral face biometric database of 168 subjects captured in 9 narrow spectral bands in VIS and NIR bands (530nm to l000nm), we illustrate the effectiveness of the proposed approach in achieving a robust and secure template protection while accounting for irreversibility, unlinkability and renewability. Through the experiments we establish the performance of the proposed template protection approach and demonstrate a high Genuine Match Rate $(GMR\approx 100\%$ at False Accept Rate of $FMR=0.01\%$ and low Equal Error Rate $EER=\approx 0\%$ , while satisfying other requirements of biometric template protection. Further, we present a security analysis of the proposed approach to demonstrate the unlinkability of the biometric templates.