Michael I. Proctor

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Realtime MRI provides useful data about the human vocal tract, but also introduces many of the challenges of processing high-dimensional image data. Intuitively, data reduction would proceed by finding the air-tissue boundaries in the images, and tracing an outline of the vocal tract. This approach is anatomically well-founded. We explore an alternative(More)
We present MRI-TIMIT: a large-scale database of synchronized audio and real-time magnetic resonance imaging (rtMRI) data for speech research. The database currently consists of speech data acquired from two male and two female speakers of Amer-ican English. Subjects' upper airways were imaged in the mid-sagittal plane while reading the same 460 sentence(More)
A method of rapid, automatic extraction of consonantal artic-ulatory trajectories from real-time magnetic resonance image sequences is described. Constriction location targets are estimated by identifying regions of maximally-dynamic correlated pixel activity along the palate, the alveolar ridge, and at the lips. Tissue movement into and out of the(More)
We explore robust methods of automatically quantifying constriction location, constriction degree and gestural kinematics of Italian short and long consonants using direct image analysis techniques applied to rtMRI data. Articulatory kinematics are estimated from correlated regional changes in pixel intensity. We demonstrate that these methods are capable(More)
A method of rapid semi-automatic segmentation of real-time magnetic resonance image data for parametric analysis of vocal tract shaping is described. Tissue boundaries are identified by seeking pixel intensity thresholds along tract-normal grid-lines. Airway contours are constrained with respect to a tract centerline defined as an optimal path over the(More)
A structural magnetic resonance imaging study has revealed that pharyngeal articulation varies considerably with voicing during the production of English fricatives. In a study of four speakers of American English, pharyngeal volume was generally found to be greater during the production of sustained voiced fricatives, compared to voiceless equivalents.(More)
PURPOSE To develop a real-time imaging technique that allows for simultaneous visualization of vocal tract shaping in multiple scan planes, and provides dynamic visualization of complex articulatory features. MATERIALS AND METHODS Simultaneous imaging of multiple slices was implemented using a custom real-time imaging platform. Midsagittal, coronal, and(More)
In order to fully understand inter-speaker variability in the acoustical and articulatory domains, morphological variability must be considered, as well. Human vocal tracts display substantial morphological differences, all of which have the potential to impact a speaker's acoustic output. The palate and rear pharyngeal wall, in particular, vary widely and(More)
Noninvasive imaging is widely used in speech research as a means to investigate the shaping and dynamics of the vocal tract during speech production. 3-D dynamic MRI would be a major advance, as it would provide 3-D dynamic visualization of the entire vocal tract. We present a novel method for the creation of 3-D dynamic movies of vocal tract shaping based(More)
Due to its aerodynamic, articulatory, and acoustic complexities, the fricative /s/ is known to require high precision in its control, and to be highly resistant to coarticulation. This study documents in detail how jaw, tongue front, tongue back, lips, and the first spectral moment covary during the production of /s/, to establish how coarticulation affects(More)