Conversational biometrics: A probabilistic view

Abstract

This article presents the concept of conversational biometrics; the combination of acoustic voice matching (traditional speaker verification) with other conversation-related information sources (such as knowledge) to perform identity verification. The interaction between the user and the verification system is orchestrated by a state-based policy modeled within a probabilistic framework. The verification process may be accomplished in an interactive manner (active validation) or as a listen-in background process (passive validation). In many system configurations, the verification may be performed transparently to the caller. For an interactive environment evaluation with uninformed impostors, it is shown that very high performance can be attained by combining the evidence from acoustics and question-answer pairs. In addition, the study demonstrates the biometrics system to be robust against fully informed impostors, a challenge yet to be addressed with existing widespread knowledge-only verification practices. Our view of conversational biometrics emphasizes the importance of incorporating multiple sources of information conveyed in speech. © 2008 Springer London.