Third International Conference on Spoken Language Processing (ICSLP 94)
The vocal-tract shapes of Japanese vowels are measured by MRI. Since the 3D figures from this measurement data are very complex, it is important to discover how much the complexity of the 3D shape brings about changes in the acoustic characteristics of vocal-tracts. We estimate the 3D effect from the complex shape by using our 3D FEM models, in which we introduce an elongation factor of the closed section. From this FEM analysis, though we see the 3D effect in the pressure distribution, we can get equivalent parameters of the one dimensional transmission line model. Moreover, we point out the effect of mechanical vibration of the larynx, and show that the movement of the laryngeal part influences the transfer function of vocal tracts even in isolated vowels or stationary vowels, because the glottis is moving as an open and close phase, or the pitch is slightly changing. Since the 3D shape also varies near the glottis, we evaluate the effect of this variation in the spectral estimation.
Bibliographic reference. Miki, Nobuhiro / Badin, Pierre / Ngoc, Y. Pham Thi / Ogawa, Yoshihiko (1994): "Vocal tract model and 3-dimensional effect of articulation", In ICSLP-1994, 167-170.