Generalized optimal thresholding for biometric key generation using face images

In this paper, we study biometric key generation using face images. Given a face image, a set of biometric features are extracted. Each feature is compared with a threshold to generate a key-bit. By cascading the key-bits from all the features, we obtain one bio-key that can be used for security applications. The performance of a biometric key generation system, determined by the chosen thresholds, can be evaluated according to reliability and security. A generalized optimal thresholding method is proposed in this paper to improve the reliability by minimizing the authentication error rate and the security by maximizing the entropy of the generated key.