Speaker verification using simplified and supervised i-vector modeling
This paper presents a simplified and supervised i-vector modeling framework that is applied in the task of robust and efficient speaker verification (SRE). First, by concatenating the mean supervector and the i-vector factor loading matrix with respectively the label vector and the linear classifier matrix, the traditional i-vectors are then extended to label-regularized supervised i-vectors. These supervised i-vectors are optimized to not only reconstruct the mean supervectors well but also minimize the mean squared error between the original and the reconstructed label vectors, such that they become more discriminative. Second, factor analysis (FA) can be performed on the pre-normalized centered GMM first order statistics supervector to ensure that the Gaussian statistics sub-vector of each Gaussian component is treated equally in the FA, which reduces the computational cost significantly. Experimental results are reported on the female part of the NIST SRE 2010 task with common condition 5. The proposed supervised i-vector approach outperforms the i-vector baseline by relatively 12% and 7% in terms of equal error rate (EER) and norm old minDCF values, respectively.