Estimating the glottal waveform and the vocal-tract filter from a vowel sound signal

A pitch-synchronous signal processing method for estimating the glottal waveform and the vocal-tract filter is presented. This method is advantageous over existing methods. First, no assumptions about the shape of the glottal wave are made in the estimation, and consequently it can be used for any types of voices. Second, it can obtain more detailed structures of the derivative of the glottal wave than using other methods. Third, the influence of the glottal wave on the estimation of the vocal-tract filter is eliminated. The glottal waveform, the derivative of the glottal wave and the vocal-tract filter obtained using this method for two vowel sounds, produced by a female and a male subject, are illustrated. This method has applications in speech pathology, speech synthesis, speaker identification and so on.