We analyzed the sibilant /s/, an unvoiced consonant, by considering turbulence and vortex sound. A segmentation technique for four dimensional magnetic resonance imaging (4D-MRI) of data considering the movements of the oral cavity is proposed. The conventional Snakes can not segment the quick deformation of the tip of the tongue in 4D-MRI images. To segment the quick motion, optical flow of 4D-MRI imaging helps give criteria for deciding the geometry of the control points of Snakes. Our proposed method utilize optical flow to modify the conventional Snakes and demonstrated superior segmentation accuracy to represent the movement of an oral cavity. Experiments demonstrated that our proposed methods accurately segmented 4D-MRI images and can thereby be used to perform numerical analyses of the sibilant /s/.
Bibliographic reference. Nozaki, Kazunori / Ohnishi, Youhei / Suda, Takeshi / Wada, Shigeo / Shimojo, Shinji (2010): "Toward aero-acoustical analysis of the sibilant /s/: an oral cavity modeling", In INTERSPEECH-2010, 1009-1012.