Harmonic All-Pole Modelling for Glottal Inverse Filtering

Glottal inverse filtering is a process, where the acoustic effect of the human vocal tract is removed from the speech signal, to obtain the flow through the vocal folds, the glottal flow. In this article, we present a fully automatic algorithm for inverse filtering, harmonic all-pole inverse filtering, that employs the harmonic structure of speech to obtain the impulse response of both the vocal tract and the glottal flow. The method assumes that the vocal tract and glottal flow waveform can be modelled with minimum- and maximum-phase AR-models, respectively, and that each glottal cycle has a distinct excitation. We present results for male and female speakers for normal, breathy and pressed voices