Contemporary Methods for Speech Parameterization

Abstract

This brief book offers a general view of short-time cepstrum-based speech parameterization and provides a common ground for further in-depth studies on the subject. Specifically, it offers a comprehensive description, comparative analysis, and empirical performance evaluation of eleven contemporary speech parameterization methods, which compute short-time cepstrum-based speech features. Among these are five discrete wavelet packet transform (DWPT)-based and six discrete Fourier transform (DFT)-based speech features and some of their variants which have been used on the speech recognition, speaker recognition, and other related speech processing tasks. The main similarities and differences in their computation are discussed and empirical results from performance evaluation in common experimental conditions are presented. The recognition accuracy obtained on the monophone recognition, continuous speech recognition, and speaker recognition tasks is contrasted against the one obtained for the well-known and widely used Mel Frequency Cepstral Coefficients (MFCC). It is shown that many of these methods lead to speech features that do offer competitive performance on a certain speech processing setup when compared to the venerable MFCC. The last does not target the promotion of certain speech features but instead aims to enhance the common understanding about the advantages and disadvantages of the various speech parameterization techniques available today and to provide the basis for selection of an appropriate speech parameterization in each particular case. In brief, this volume consists of nine sections. Section 1 summarizes the main concepts on which the contemporary speech parameterization is based and offers some background information about their origins. Section 2 introduces the objectives of speech pre-processing and describes the processing steps that are commonly used in the contemporary speech parameterization methods. Sections 3 and 4 offer a comprehensive description and a comparative analysis of the DFT- and DWPT-based speech parameterization methods of interest. Sections 5–7, present results from experimental evaluation on the monophone recognition, continuous speech recognition, and speaker recognition tasks, respectively. 8 offers concluding remarks and outlook for possible future targets of speech parameterization research. Finally, Sect. 9 provides some links to other sources of information and to publically available software, which offer ready-to-use implementations of these speech features.