1Division of Oral Rehabilitation Medicine, Department of Special Needs Dentistry, Showa University School of Dentistry, 2Graduate School of Engineering, Tokyo City University, 3Seiai Rehabilitation Hospital
ultrasonic diagnosis, tongue movement, Japanese speech, three-dimensional tongue-shaped standard model
Purpose: It is difficult to obtain clear three-dimensional (3D) moving images with existing ultrasound systems. In order to investigate tongue movements during Japanese speech, we have developed a 3D tongue-shaped standard model (3D model) on a personal computer based on volume data of ultrasound tongue images. In this paper, the method for 3D model construction is discussed. Subjects and Methods: The subject was a 34-year-old female. Ultrasound tongue images while at rest and while producing five Japanese vowels were taken, and the tomographic data of the images were obtained with 4-mm slice intervals. To acquire the tongue surface line, inflection points of the tongue surface were selected as control points. A spline curve was derived based on the control points, and a tongue surface (spline surface) was generated from a set of spline curves that corresponded to the ultrasound slice images. Thus, the 3D model was constructed. Results and Discussion: By using our method, 3D models of the tongue surface were constructed. It will be possible to produce the 3D images in a shorter time by automating the selection of control points. In addition, it may be possible to observe tongue movement in detail by constructing 3D moving images based on the interpolation of a set of sequential 3D model data. Conclusion: By using our method, it may be possible to analyze disordered tongue movements during speech and explain the tongue status to patients in a clinical setting.