The Intelligent Voice 2016 Speaker Recognition System
Table 2: Performance comparison of the Intelligent Voice speaker recognition system with various analysis on the development protocol of NIST SRE 2016.
['[BOLD] Acoustic Features', '[BOLD] Unequalized EER', '[BOLD] Unequalized  [ITALIC] Cmindet', '[BOLD] Unequalized  [ITALIC] Cdet', '[BOLD] Equalized EER', '[BOLD] Equalized  [ITALIC] Cmindet', '[BOLD] Equalized  [ITALIC] Cdet']
In this section we present the results obtained on the protocol provided by NIST on the development set which is supposed to mirror that of evaluation set. The first part of the table indicates the result obtained by the primary system. As can be seen, the fusion of MFCC and PLP (a simple sum of both MFCC and PLP scores) resulted in a relative improvement of almost 10%, as compared to MFCC alone, in terms of both Cdet and Cmindet. In order to quantify the contribution of the different system components we have defined different scenarios. In scenario A, we have analysed the effect of using LDA instead of NDA. As can be seen from the results, LDA outperforms NDA in the case of PLP, however, in fusion we can see that NDA resulted in better performance in terms of the primary metric. Results indicate superior performance using this technique. In scenario C, we investigated the effects of language normalization on the performance of the system. If we replace LN-LDA with simple LDA, we can see performance degradation in MFCC as well as fusion, however, PLP seems not to be adversely affected. For our secondary submission, we incorporated a disjoint portion of the labelled development set (10 out of 20 speakers) in either LN-LDA and in-domain PLDA training. We evaluated the system on almost 6k out of 24k trials from the other portion to avoid any over-fitting, particularly important for the domain adaptation technique. This resulted in a relative improvement of 11% compared to the primary system in terms of the primary metric. However, the results can be misleading, since the recording condition may be the same for all speakers in the development set.