The Complementary Registration Method for Vocal Tract of Sibilant /s/

We analyzed the sibilant /s/, an unvoiced consonant, by considering turbulence and vortex sound. The morphology of an oral tract is required when doing numerical analyses, and because magnetic resonance imaging (MRI) and cone-beam computed tomography (CBCT) are complementary, we use them as the registration technique in our proposed method. Calculating the approximate function to represent the morphological features of these geometries enabled us to associate the MRI and CBCT datasets with each other by referring to the functions in our proposal method. We applied the method to an actual person's 4-dimensional MRI and CBCT datasets, and as a result were able to determine the appropriate registration result. The result was validated in a special configuration in which the result image was compared with the CBCT image of an actual person's oral tract while pronouncing sibilant /s/. The validation demonstrates how our proposed method accurately registers the MRI and CBCT datasets and can thereby be used to perform numerical analyses in speech science research.