Digital Image Correlation

1
Digital Image Correlation

• Steve McNeill, PhD, PE
• University of South Carolina
• Department of Mechanical Engineering
• Columbia, SC 29212
• mcneill_at_sc.edu

2
Digital Image Correlation?

• A non-contacting method of measuring surface
  displacements of an object subjected to a driving
  force.

3
Digital Image Correlation?

• Uses video camera to record images of the surface
  which are then analyzed to determine the surface
  deformation.

4
Digital Image Correlation?

• 2-D 3-D versions
• 2-D, only one camera. Motion must be in plane
• 3-D, two cameras. Motion can be anything as long
  as it can be seen by the camera.

5
History of Digital Image Correlation

• 1980 USCs Drs. Ranson, Peters and graduate
  student Chu
• 2-D
• Single Point
• Large amount of user interaction
• Required good guess
• Mini-computer (VAX 11/780)
• Up to a day to get the single point

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History of Digital Image Correlation

• 1982 USCs Drs. Ranson, Peters, Sutton and
  graduate student McNeill
• 2-D
• A field of points
• User interaction required for initial point
• Required reasonable guess
• Mini-computer (VAX 11/780)
• First PC version, 30 minutes per point
• Problems with out-of-plane motion recognized

7
History of Digital Image Correlation

• 1986 USCs Drs. Ranson, Peters, Sutton, Chao
  received NSF funding for 3-D
• Dual camera
• Complex calibration
• 1 day of user interaction to calibrate
• Non-deforming subsets
• Mini-computer (VAX 11/780)
• Some data obtained but not feasible to use

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History of Digital Image Correlation

• 1988 USCs Drs. Sutton and McNeill with graduate
  student Miao
• 3-D
• Simple grid calibration
• 2 step calibration process
• Non-deforming subsets
• Work station computer
• Calibration touchy and required good guesses

9
History of Digital Image Correlation

• 1992 USCs Drs. Sutton and McNeill with graduate
  student Helm
• 3-D
• Simple grid calibration
• Improved 2 step calibration process
• Deforming subsets
• PC computer
• Visual initial guess generator
• First truly practical 3-D image correlation

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History of Digital Image Correlation

• 1998 USCs Drs. Sutton and McNeill with graduate
  student Schreier
• 3-D
• No grid needed for calibration
• Distortion correction
• Deforming subsets
• Fast 1,000 points per second
• Bi-Cubic spline interpolation for lower error
• Commercial product

11
History of Digital Image Correlation

• 2003 USCs Drs. Sutton, McNeill, Garcia
  Schreier with graduate students Cornille Sands
• 2-D 3-D
• Scanning electron microscope
• First measurements at nano and micro scale
• High speed correlation 10,000 frames per second
• Ultra-high speed 200,000,000 frames per second

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How does it work?
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How does it work?
Pixel
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How does it work?
Pixel
100
0
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How does it work?
100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100
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How does it work?
100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100
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How does it work?
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How does it work?
100 100 100 100 0 0 0 100 100 100 100
100 100 0 0 0 100 100 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 100 100 100
100 0 0 0 100 100 100 100 100 100 0
0 0 100 100 100 100 100 100 0 0 0
100 100 100 100 100 100 0 0 0 100 100
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How does it work?
100 100 100 100 0 0 0 100 100 100 100 100
100 0 0 0 100 100 0 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 100 100 100 100 0 0
0 100 100 100 100 100 100 0 0 0 100 100
100 100 100 100 0 0 0 100 100 100 100
100 100 0 0 0 100 100
100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100
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How does it work?
100 100 100 100 0 0 0 100 100 100 100 100
100 0 0 0 100 100 0 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 100 100 100 100 0 0
0 100 100 100 100 100 100 0 0 0 100 100
100 100 100 100 0 0 0 100 100 100 100
100 100 0 0 0 100 100
100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100
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How does it work?
100 100 100 100 0 0 0 100 100 100 100 100
100 0 0 0 100 100 0 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 100 100 100 100 0 0
0 100 100 100 100 100 100 0 0 0 100 100
100 100 100 100 0 0 0 100 100 100 100
100 100 0 0 0 100 100
100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100
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How does it work?
100 100 100 100 0 0 0 100 100 100 100 100
100 0 0 0 100 100 0 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 100 100 100 100 0 0
0 100 100 100 100 100 100 0 0 0 100 100
100 100 100 100 0 0 0 100 100 100 100
100 100 0 0 0 100 100
100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100
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How does it work?
100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100
100 100 100 100 0 0 0 100 100 100 100 100
100 0 0 0 100 100 0 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 100 100 100 100 0 0
0 100 100 100 100 100 100 0 0 0 100 100
100 100 100 100 0 0 0 100 100 100 100
100 100 0 0 0 100 100
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100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100
100 100 100 100 0 0 0 100 100 100 100 100
100 0 0 0 100 100 0 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 100 100 100 100 0 0
0 100 100 100 100 100 100 0 0 0 100 100
100 100 100 100 0 0 0 100 100 100 100
100 100 0 0 0 100 100
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100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100
100 100 100 100 0 0 0 100 100 100 100 100
100 0 0 0 100 100 0 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 100 100 100 100 0 0
0 100 100 100 100 100 100 0 0 0 100 100
100 100 100 100 0 0 0 100 100 100 100
100 100 0 0 0 100 100
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How does it work?
100 100 100 100 0 0 0 100 100 100 100 100
100 0 0 0 100 100 0 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 100 100 100 100 0 0
0 100 100 100 100 100 100 0 0 0 100 100
100 100 100 100 0 0 0 100 100 100 100
100 100 0 0 0 100 100
100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 100 100 100 0 0 0 100 100 100 100 100 100
0 0 0 100 100 100 100 100 100 0 0 0
100 100 100
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How does it work?
What the numbers really look like
103 98 103 102 2 3 1 102 99 99 101
102 103 2 2 1 101 101 3 1 3
1 2 1 2 3 3 1 3 2
0 0 1 1 2 2 2 2 1
4 2 3 1 2 0 102 100 100 104 0
1 0 101 103 100 99 97 101 2 2 0
101 99 102 102 100 101 1 2 3 97
100 101 103 102 99 1 0 2 100 97
101 103 99 3 0 1 100 98 102 99 101
102 1 2 3 103 102 101 102 101 99 3 2
2 102 101 99 1 3 2 1 0 1 3
1 3 2 1 0 3 2 2 2
3 1 3 2 1 1 2 3 1 1
1 102 97 101 3 0 0 99 103 97 99
103 101 2 2 2 97 101 102 102 98 102 1
3 2 102 99 101
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How does it work?
What the numbers really look like
103 98 103 102 2 3 1 102 99 99 101
102 103 2 2 1 101 101 3 1 3
1 2 1 2 3 3 1 3 2
0 0 1 1 2 2 2 2 1
4 2 3 1 2 0 102 100 100 104 0
1 0 101 103 100 99 97 101 2 2 0
101 99 102 102 100 101 1 2 3 97
100 101 103 102 99 1 0 2 100 97
101 103 99 3 0 1 100 98 102 99 101
102 1 2 3 103 102 101 102 101 99 3 2
2 102 101 99 1 3 2 1 0 1 3
1 3 2 1 0 3 2 2 2
3 1 3 2 1 1 2 3 1 1
1 102 97 101 3 0 0 99 103 97 99
103 101 2 2 2 97 101 102 102 98 102 1
3 2 102 99 101
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How does it work?
What the numbers really look like
103 98 103 102 2 3 1 102 99 99 101
102 103 2 2 1 101 101 3 1 3
1 2 1 2 3 3 1 3 2
0 0 1 1 2 2 2 2 1
4 2 3 1 2 0 102 100 100 104 0
1 0 101 103 100 99 97 101 2 2 0
101 99 102 102 100 101 1 2 3 97
100 101 103 102 99 1 0 2 100 97
101 103 99 3 0 1 100 98 102 99 101
102 1 2 3 103 102 101 102 101 99 3 2
2 102 101 99 1 3 2 1 0 1 3
1 3 2 1 0 3 2 2 2
3 1 3 2 1 1 2 3 1 1
1 102 97 101 3 0 0 99 103 97 99
103 101 2 2 2 97 101 102 102 98 102 1
3 2 102 99 101
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How does it work?
Sub Pixel Movement
103 98 103 50 2 3 51 101 99 99 101
102 53 2 2 51 100 101 3 1 3
1 2 1 2 3 3 1 3 2
0 0 1 1 2 2 2 2 1 4
2 3 1 2 0 102 100 100 52 0 1
50 99 103 100 99 97 50 2 2 50
102 99 102 102 100 49 1 2 53 103
100 101 103 102 48 1 0 52 97 97
101 103 99 3 0 1 100 98 102 99 101
102 1 2 3 103 102 101 102 101 99 3 2
2 102 101 99 1 3 2 1 0 1 3
1 3 2 1 0 3 2 2 2
3 1 3 2 1 1 2 3 1 1
1 102 97 101 3 0 0 99 103 97 99
103 101 2 2 2 97 101 102 102 98 102 1
3 2 102 99 101
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How does it work?
Sub Pixel Movement
103 98 103 50 2 3 51 101 99 99 101
102 53 2 2 51 100 101 3 1 3
1 2 1 2 3 3 1 3 2
0 0 1 1 2 2 2 2 1 4
2 3 1 2 0 102 100 100 52 0 1
50 99 103 100 99 97 50 2 2 50
102 99 102 102 100 49 1 2 53 103
100 101 103 102 48 1 0 52 97 97
101 103 99 3 0 1 100 98 102 99 101
102 1 2 3 103 102 101 102 101 99 3 2
2 102 101 99 1 3 2 1 0 1 3
1 3 2 1 0 3 2 2 2
3 1 3 2 1 1 2 3 1 1
1 102 97 101 3 0 0 99 103 97 99
103 101 2 2 2 97 101 102 102 98 102 1
3 2 102 99 101
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How does it work?
Sub Pixel Movement
103 98 103 50 2 3 51 101 99 99 101
102 53 2 2 51 100 101 3 1 3
1 2 1 2 3 3 1 3 2
0 0 1 1 2 2 2 2 1 4
2 3 1 2 0 102 100 100 52 0 1
50 99 103 100 99 97 50 2 2 50
102 99 102 102 100 49 1 2 53 103
100 101 103 102 48 1 0 52 97 97
101 103 99 3 0 1 100 98 102 99 101
102 1 2 3 103 102 101 102 101 99 3 2
2 102 101 99 1 3 2 1 0 1 3
1 3 2 1 0 3 2 2 2
3 1 3 2 1 1 2 3 1 1
1 102 97 101 3 0 0 99 103 97 99
103 101 2 2 2 97 101 102 102 98 102 1
3 2 102 99 101
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How does it work?
0
0
100
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How does it work?
0
0
100
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How does it work?
0
0
100
0
100
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How does it work?
0
0
100
50
0
100
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How does it work?
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Image Correlation
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Example
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Example
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Example
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Software
VIC 2-D VIC 3-D VIC 2-D on lab computers B202.
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Software
VIC 2-D VIC 3-D VIC 2-D on lab computers Wed.
www.correlatedsolutions.com
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Questions?