On the Performance Degradation of Speaker Recognition System due to Variation in Speech Characteristics Caused by Physiological Changes

Abstract

Speaker recognition is the process of identifying a person using their speech characteristics (voice biometrics). Speech characteristics of an individual can vary due to physiological changes which may be caused by health changes, physical activity as well as emotional changes. Such changes in speech characteristics are likely to affect the accuracy of speaker recognition systems. In this paper, the performance degradation of a speaker recognition system is quantified, empirically, when the characteristics of an individual's speech change due to physiological changes caused by 'physical activity'. The speaker recognition system used in this work is based on Mel-Frequency Cepstrum Coefficients (MFCC's) and Vector Quantization (VQ). When the speech sample of a user is obtained soon after high intensity physical activity, the changes in the individual’s speech characteristics affect the accuracy of speaker recognition systems. It is necessary to understand how speaker recognition systems are affected by changes in speech characteristics in order to improve their immunity to such changes. From speech recorded after physical activity, it is found that the duration of ‘voiced component’ which has prominent discriminative characteristics of speech is shortened and it has an effect on the accuracy of speaker recognition system.