Vowel synthesis using a vocal tract mapping interface and simulation study of inverse mapping

Abstract

We have developed a vocal-tract mapping interface to produce vowel sounds. The interface provides an easy and effective setting of the vocal tract shape with a simple mouse click on its interface window. A vocal tract shape at the mouse position on the interface window is calculated by interpolation based on the prepared vocal tract shapes. In this paper, the features and advantages of the interface are shown through examples of the generated formant frequencies. In addition, the inverse estimation of the vocal tract shape from formant frequencies is studied as one of its applications. In this inverse method, the possible region having the solution on the interface window is determined based on the changes in the formant frequencies in the first-stage search. A coarse-to-fine algorithm is used to determine the pixel-point on the window as the solution in the second-stage search. The usefulness of the proposed method is shown through simulation results.