Analyses of vocal tract cross-distance to area mapping: an investigation of a set of vowel images.

Traditional models of mappings from midsagittal cross-distances to cross-sectional areas use only local cross-distance information. These are not the optimal models on which to base the construction of a mapping between the two domains. This can be understood because phonemic identity can affect the relation between local cross-distance and cross-sectional area. However, phonemic identity is not an appropriate independent variable for the control of an articulatory synthesizer. Two alternative approaches for constructing cross-distance to area mappings that can be used for articulatory synthesis are presented. One is a vowel height-sensitive model and the other is a non-parametric model called loess. These depend on global cross-distance information and generally perform better than the traditional models.