Bayesian distance metric learning on i-vector for speaker verification

• Main Author: Fang, Xiao, Ph. D. Massachusetts Institute of Technology
• Other Authors: James R. Glass and Najim Dehak., Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science.
• Format: Thesis
• Language: English
• Published: Massachusetts Institute of Technology 2013
• Subjects: Electrical Engineering and Computer Science; Fang; DML
• Online Access: http://hdl.handle.net/1721.1/84870

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2013. Cataloged from PDF version of thesis. Includes bibliographical references (pages 63-66). This thesis explores the use of Bayesian distance metric learning (Bayes_dml) for the task of speaker verification using the i-vector feature representation. We propose a framework that explores the distance constraints between i-vector pairs from the same speaker and different speakers. With an approximation of the distance metric as a weighted covariance matrix of the top eigenvectors from the data covariance matrix, variational inference is used to estimate a posterior distribution of the distance metric. Given speaker labels, we select different-speaker data pairs with the highest cosine scores to form a different-speaker constraint set. This set captures the most discriminative between-speaker variability that exists in the training data. This system is evaluated on the female part of the 2008 NIST SRE dataset. Cosine similarity scoring, as the state-of-the-art approach, is compared to Bayes-dml. Experimental results show the comparable performance between Bayes_dml and cosine similarity scoring. Furthermore, Bayes-dml is insensitive to score normalization, as compared to cosine similarity scoring. Without the requirement of the number of labeled examples, Bayes_dml performs better in the context of limited training data by Xiao Fang. S.M.