Simplification of vocal tract shapes with different levels of detail

We propose a semi-automatic method to regenerate simplified vocal tract geometries from very detailed input (e.g. MRI-based geometry) with the possibility to control the level of detail, while maintaining the overall properties. The simplification procedure controls the number and organization of the vertices in the vocal tract surface mesh and can be assigned to replace complex cross-sections with regular shapes. Six different geometry regenerations are suggested: bent or straight vocal tract centreline, combined with three different types of cross-sections; namely realistic, elliptical or circular. The key feature in the simplification is that the cross-sectional areas and the length of the vocal tract are maintained. This method may, for example, be used to facilitate 3D finite element method simulations of vowels and diphthongs and to examine the basic acoustic characteristics of vocal tract in printed physical replicas. Furthermore, it allows for multimodal solutions of the wave equation.