Improved Phonetic Speaker Recognition Using Lattice Decoding

Abstract

The current "state-of-the-art" in phonetic speaker recognition uses relative frequencies of phone n-grams as features for training speaker models and for scoring test-target pairs. Typically, these relative frequencies are computed from a simple 1-best phone decoding of the input speech. We present results on the Switchboard-2 corpus, where we compare 1-best phone decodings versus lattice phone decodings for the purposes of performing phonetic speaker recognition. The phone decodings are used to compute relative frequencies of phone bigrams, which are then used as inputs for two standard phonetic speaker recognition systems, a system based on log-likelihood ratios (LLRs) (Andrews, W.D. et al., Proc. Eurospeech, p.149-53, 2001; Proc. ICASSP, vol.I, p.149-53, 2002), and a system based on support vector machines (SVMs) (Campbell, W.M. et al., Advances in Neural Information Processing Systems, vol.16, 2004). In each experiment, the lattice phone decodings achieve relative reductions in equal-error rate (EER) of between 31% and 66% below the EERs of the 1-best phone decodings. Our best phonetic system achieves an EER of 2.0% on 8-conversation training and 1.4% when combined with a GMM-based system.