3-D Digital Image Correlation/Profiling Test

A recently performed test by the team at USC involved profiling the surface of a small object. This object in particular was chosen to be the face of our first president George Washington... on the front of a quarter. The whole test consisted of only a few hours with the help of our own Visual Basic code, and an SGI program for surface fitting and display written by the Computer Science department at Stanford University. The first test was run calculating coordinates for approximately 3500 points. These images can be viewed if desired from the links below, although the second and third test results are more exciting. The first image was smoothed to reduce the polygonal mesh lattice distortion.

Quarter - 3500 points smoothed
Quarter - 3500 points unsmoothed

The second test was performed using the coordinates of approximately 20,000 points and the same 15x15 correlation subset. This improved the overall resolution. Thumbnails of some of the test images are shown below. The first and second images are smoothed and unsmoothed respectively as before, and the third is shown with a contour map scaled in mm. The fourth image is rotated so that profile elevations may be seen more clearly.

Click on a thumbnail to see the full-size image.

quarter2-t.jpg - 3.2 K

Quarter - 20,000 points smoothed

quarter2-t.jpg - 3.2 K

Quarter - 20,000 points unsmoothed

contour-t.jpg - 5.2 K

Quarter - scaled contour (total image approx. 12mm sq.)

q2-smooth-t.jpg - 3.1 K

Quarter - 20,000 points rotated

The third correlation was performed with the same 20,000 points, but with an even smaller subset of 10x10. This allowed us to obtain a higher accuracy as well as improved resolution. This test took 12 hours to run and returned remarkable features. As before, the thumbnails below depict the first being smoothed and the second unsmoothed.

q3-smooth-t.jpg - 3.5 K

Quarter - 20,000 points smoothed with 10x10 subset (pick this one!)

quarter3-t.jpg - 3.6 K

Quarter - 20,000 points unsmoothed

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