Estimating vocal-tract area functions from vowel sound signals over closed glottal phases

Existing methods that estimate the vocal-tract area functions (VTAF) from vocal-tract filters (VTF) using speech signals suffer from inadequate elimination of the glottal wave, and the influence of non-ideal vocal-tract boundary conditions. To minimize these effects on the VTF estimation, we present a method that jointly estimates the glottal wave and the VTF corresponding to closed glottal phases. Experimental results show that our method yields better estimates. The VTAF obtained for /a/ and /i/ each produced by a female and a male subject show that more detailed and accurate VTAF are obtained using the speech signals corresponding to closed glottal phases.