An MRI-based Morphological Approach to Vocal Tract Area Function Estimation

• Main Author: Tiede, Mark Kenneth
• Format: Dissertation
• Language: English
• Subjects: language, linguistics
• ISBN: 1303299232; 9781303299230

Volumetric MRI data has been collected during the sustained production of American English and Japanese vowels. Six native speakers (5 male, 1 female) produced nine steady-state American English vowels, and six native speakers (5 male, 1 female) produced the Japanese five vowel inventory. New methods have been developed for identifying the vocal tract airway within such data, resulting in a characterization of cross-sectional area that preserves shape information. Results have been tested through comparison of transfer function spectra derived from these characterizations with those obtained from recorded productions from the same speakers.
In addition to reporting standard area function results, a novel form of parameterization is described that can be used to estimate the vocal tract shape associated with a target vowel from just four weights. Because it provides a mapping between some offset along the tract and the corresponding cross-sectional shape, this 'shape-based' approach can be viewed as a superset of existing area function predictors, since area is readily obtained from polygonal shape by triangulation methods.