PARAFAC Analysis of 3-D Tongue Shape Yanli Zheng, Mark Hasegawa-Johnson ECE Department University of Illinois at Urbana-Champaign

WHY is the factor analysis of tongue shape meaningful? Part I. Background WHY is the factor analysis of tongue shape meaningful? Speech Motor System

Part I. Background (cont. Why?) 2. Representing Vowel Frequency Domain Anatomical View Basic Vowel Diagram The vowel chart is quite a complicated looking diagram. All that it is trying to do is to represent where the tongue lies in relation to the openness of the mouth when you sound a vowel. So the front closed vowel /i:/ means that your tongue is in a forward position in the mouth which is in a relatively closed position. Try saying it to yourself and then contrast it with the open back sound in the diagram.

HOW to analysis the vowels in the context of anatomy? Part I. Background HOW to analysis the vowels in the context of anatomy? 2-D PARAFAC analysis by Richard Harshman(1977) X-ray images Measuring Scheme

Background (cont. Results of Harshman) Results:Two Factors account for 92% variance. Vowels Loading Grids Factors

Part I. Background Why is 3D Different from 2D? Linear Source-Filter Theory: Vowel Quality is Determined by Areas Area Correlated w/Midsagittal Width Distinguish important in Speech Synthesis Clinic Application

Part II. Algorithms Introduction PARAFAC (Parallel Factor Analysis) xijk: tongue shape measurement for ith data point, jth vowel and kth speaker. aif: fth factor contribution to ith data point bjf: loading of phoneme j on fth factor ckf: loading of speaker k on fth facotor

Part II. Algorithms Introduction 2. Tucker3 Model(used in the validation of PARAFAC model)

Part III. 3-D Factor Analysis of MRI-Derived Tongue Shapes Subjects: 5 subjects successfully imaged (three male speaker: m1,m2, m3; and two female speaker: f1,f2). MRI Image Collection T1-weighted GE Signa 1.5T 3mm slices 24 cm FOV 256 x 256 pixels Coronal, Axial 11-18 Sounds per Subject. Breath-hold in vowel position for 25 seconds

Display series of CT or MR image slices Part III. 3-D Factor Analysis of MRI-Derived Tongue Shapes 3. Image Viewing and Segmentation: the CTMRedit GUI and toolbox Display series of CT or MR image slices Segment ROI manually or automatically Interpolate and reconstruct ROI in 3D space This is how CTMRedit looks. As I have already mentioned in previous viewgraph, the goal of CTMRedit is to be able to load and display series of CT or MR image slides in any standard image format with zoom in&out functions, and segment the region of interest both manually or automatically with good accuracy, and to perform good interpolation between segmented ROI on each slices so that we can reconstruct 3D ROI for further analysis. We can retrieve an absolute coordinate data on 3D ROI. Therefore, it does not just render the 3D image, but it reconstructs 3D images. This tool not only displays 3D ROI with some routine jobs such as an rotation or changing view angles, but it also calculates accurate absolute 3D x,y,z spatial data so that we, engineers can easily perform various analysis such as acquiring a statistical data on a certain shape of 3D ROI.

2) How to define the measuring grid? Part III. 3-D Factor Analysis of MRI-Derived Tongue Shapes 4. PARAFAC Analysis 3D-Tongue Shape 2) How to define the measuring grid?

Part III. 3-D Factor Analysis of MRI-Derived Tongue Shapes 4 Part III. 3-D Factor Analysis of MRI-Derived Tongue Shapes 4. PARAFAC Analysis(cont.) 3) Result: 2 Factors are extracted, with 83.8729 % variance explained

Split-half test (example for f1,f2 and m3) Part III. 3-D Factor Analysis of MRI-Derived Tongue Shapes 4)Validation of the Result Split-half test (example for f1,f2 and m3) Correlation Coefficients Grid Contribution 0.9646 Vowel Loading 0.9279

4)Validation of the Result b) Check the reliability of the solution Try different start points, check whether all the solutions converge to the same solution. c) Core Consistency Testing (by Rasmus Bro,1998)

Degenerated result for 3-factor PARAFAC Model Correlation Coefficients 1&2 2&3 1&3 Grid Contribution -0.5362 0.9632 -0.6045

2. Lay the foundation for future research with disordered populations. Part IV. Conclusion 3-D PARAFAC Analysis of Tongue Shape suggests the “Hierarchical Control” This research and the follow-up expected research in the MR Microscopy, and Dynamic Imaging aim to : 1. Provide new anatomical information to speech scientists and speech pathologists 2. Lay the foundation for future research with disordered populations.