A novel technique for the combination of utterance and speaker verification systems in a text-dependent speaker verification task

In this paper we present a novel technique for combining a Speaker Verification System with an Utterance Verification System in a Speaker Authentication system over the telephone. Speaker Verification consists in accepting or rejecting the claimed identity of a speaker by processing samples of his/her voice. Usually, these systems are based on HMM's that try to represent the characteristics of the talkers' vocal tracts [1]. Utterance Verification systems make use of a set of speakerindependent speech models to recognize a certain utterance and decide whether a speaker has uttered it or not. If the utterances consist of passwords, this can be used for identity verification purposes [2][3]. Up to now, both techniques have been used separately. This paper is focused on the problem of how to combine these two sources of information. A new architecture is presented to join an utterance verification system and a speaker verification system in order to improve the performance in a textdependent speaker verification task.