PARAFAC Analysis of 3D Tongue Shape

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PARAFAC Analysis of 3-D Tongue Shape

• Yanli Zheng, Mark Hasegawa-Johnson
• ECE Department
• University of Illinois at Urbana-Champaign

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Part I. Background

• WHY is the factor analysis of tongue shape
  meaningful?
• Speech Motor System

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Part I. Background (cont. Why?)
2. Representing Vowel

• Anatomical View Basic Vowel Diagram

• Frequency Domain

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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
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Background (cont. Results of Harshman)
ResultsTwo Factors account for 92 variance.

Vowels Loading
Grids Factors
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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

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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

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Part II. Algorithms Introduction

• 2. Tucker3 Model(used in the validation of
  PARAFAC model)

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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

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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

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Part III. 3-D Factor Analysis of MRI-Derived
Tongue Shapes 4. PARAFAC Analysis

• 3D-Tongue Shape

• 2) How to define the measuring grid?

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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
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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

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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)

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Degenerated result for 3-factor PARAFAC Model

• Correlation
  Coefficients
• 12
  23 13
• Grid Contribution -0.5362 0.9632
  -0.6045

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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.