LSF Aliasing Removal for Improved Speaker Verification

Abstract

Applications such as transaction authentication may require speaker recognition systems to operate on compressed speech transmitted over mobile phone networks. However, speech compression degrades speech quality, and hence causes a reduction in recognition performance. It has been shown that the classic technique for extraction of Line Spectral Frequency (LSF) parameters in speech coders is prone to aliasing distortion. The use of a low-pass filtering on upsampled LSF vectors has been shown to alleviate this problem, therefore improving speech quality. In this paper, the effect of this Non-Aliased LSF (NA-LSF) extraction method on speaker recognition performance is observed using GSM-EFR coded speech. When the NA-LSFs are used in the coder the verification performance loss introduced by the GSM-EFR is reduced, producing similar performance to uncoded speech.