Analysis of Excitation Source Characteristics for Shouted and Normal Speech Classification

Abstract

The present work is aimed at analysing the excitation source characteristics of normal and shouted speech. In this context, we analyze the Differenced Electroglottogram (DEGG) signal corresponding to different vowels. This work proposes two novel excitation source features that are estimated from DEGG signal. These features are (a) Open Phase Triangle Area (OPTA) and (b) Flatness of Glottal Cycle (FoGC). OPTA captures the effect of open phase duration and slope of DEGG signal. FoGC measures the change in source characteristics due to strength of excitation (SoE) and pitch period. A practical issue in using the proposed features is the unavailability of DEGG signal in most speech processing applications. To overcome this problem, the integrated linear prediction residual (ILPR) signal estimated from speech is considered as an approximation of DEGG. We show that the proposed features can be computed from ILPR signal in the absence of DEGG. It is observed that the proposed features (estimated from either DEGG or ILPR) are successful in discriminating shouted from normal speech.