Estimation of area function for three-dimensional vocal tract using finite-element method

Abstract

Numerous studies have obtained a vocal tract area function using data obtained from magnetic resonance imaging (MRI). However, this approach often results in increased error between formant frequencies derived by recorded voice and estimated frequencies derived by MRI. Two factors engender error: creating the vocal tract model and estimating the area function from the vocal tract model. Generally, the errors from those two factors are not considered independently. This study is intended to establish precise estimation of the area function automatically from a vocal tract model. Pressure contours and sound intensity in the vocal tract are obtained using the finite-element method (FEM); the vocal tract area function is obtained from them. The precision is assessed by comparing the formant frequencies that are derived using the FEM with our method. Results show that the vocal tract area function can be estimated precisely from three-dimensional MRI.