Acoustic Model Enhancement: An Adaptation Technique for Speaker Verification Under Noisy Environments

This work presents an acoustic model adaptation method for speaker verification (SV) in environments with additive noise. In contrast to traditional acoustic model adaptation techniques that adapt the models parameters based on a model of the noise, acoustic model enhancement (AME) belongs to a new scheme in which the models are adapted to the speech enhancement strategy. The theoretical framework is presented for spectral subtraction (SS) as the enhancement technique and GMM as the acoustic models. In order to study the effect of additive noise only, a modified TIMIT dataset was used. The experimental setup uses two types of noise: one with fixed spectrum that helps as a proof of concept, and another with time-varying spectrum as a more realistic performance reference for AME. The results for this latter type show that at 20 dB SNR, the equal error rate (EER) dropped from 17% to around 8.9% when the noisy speech was enhanced with SS, whereas it further dropped to 8.1% with AME.