Probabilistic face authentication using Hidden Markov Models

In this paper a novel approach for face authentication is proposed, based on the Hidden Markov Model (HMM) tool. While this technique has been largely and successfully employed in face recognition systems, its use in the authentication context has poorly been investigated. The method proposed in this paper extracts from the image a sequence of partially overlapped images, from which different kinds of simple and quickly computable features are extracted. The face template is obtained by modelling the sequence with a continuous Gaussian Hidden Markov Model. Given an unknown subject, the authentication phase is carried out by thresholding the likelihood of the given face with respect to the HMM template. The proposed approach has been thoroughly tested on the ORL database, also applying different parameters' configurations. A comparison with two other state-of-the-art approaches is also reported. The results obtained are really promising, showing the wide applicability of the Hidden Markov Models methodology.