Application of zero-frequency filtering for vowel onset point detection

Abstract

Vowel onset points in speech signals, are the instances where the voicing of the vowels begin. These points serve as important landmarks for the analysis as well as synthesis of speech signals. These landmarks help to identify the information about the behaviour of transition of several different sounds into and out of the vowel regions. In this paper, we propose a new method to identify vowel onset points for a speech signal using the zero frequency filtered (ZFF) speech signal and its frequency spectrum. The ZFF signal is obtained by passing the speech signal through a resonator with central frequency as 0 Hz. Therefore, ZFF signal essentially contains the low pass components of a given speech signal. Vowels are mostly characterized by the significant energy content in the relatively low frequency bands. Significant improvement in VOP detection performance is observed using proposed method compared to existing methods.