pieyj / vop-detection

Vowel onset point detection is done using modulation spectrum energy.

VOP-Detection

Vowel onset point (VOP):

Vowel Onset Point is the instant at which the beginning of a vowel takes place during speech production. A speech signal is composed of voiced signal, unvoiced signal and noise. Vowels along with few consonants a considered as voiced while others as unvoiced.
Voiced speech is produced by vibrations in vocal cords thus can have high energy compared to unvoiced speech which are low energy. There are significant changes occurring in the energies of excitation source, spectral peaks, and modulation spectrum at the point when a vowel is pronounced in speech. So our project is to detect Vowel onset point using modulation spectrum energy.
Significance of using modulation spectrum energy: Modulation components refer to the slowly varying temporal envelope components in speech. Temporal envelope of speech is dominated of low frequency components by several Hertz.
Thus, the onset of vowel may be manifested as a significant change in the modulation spectrum energy level in the 4–16 Hz band.

So we have done Vowel onset point detection using modulation spectrum energy.