Speaker Recognition Using e-Vectors

Systems based on i-vectors represent the current state-of-the-art in text-independent speaker recognition. Unlike joint factor analysis (JFA), which models both speaker and intersession subspaces separately, in the i-vector approach all the important variability is modeled in a single low-dimensional sub-space. This paper is based on the observation that JFA estimates a more informative speaker subspace than the "total variability" i-vector subspace, because the latter is obtained by considering each training segment as belonging to a different speaker. We propose a speaker modeling approach that extracts a compact representation of a speech segment, similar to the speaker factors of JFA and to i-vectors, referred to as "e-vector." Estimating the e-vector subspace follows a procedure similar to i-vector training, but produces a more accurate speaker subspace, as confirmed by the results of a set of tests performed on the NIST 2012 and 2010 Speaker Recognition Evaluations. Simply replacing the i-vectors with e-vectors we get approximately 10% average improvement of the C-primary cost function, using different systems and classifiers. It is worth noting that these performance gains come without any additional memory or computational costs with respect to the standard i-vector systems.