Experimental Results
Rotation
In this example a fingertip is pressed firmly against a flat surface and rotated. At frame 70, the fingertip begins a counter-clockwise rotation. Most of the fingertip is sticking to the glass. The top part of the finger is moving up, stretching the intermediate zone between the moving and non-moving segments. The right-hand part is moving toward the upper-left corner, resulting in compression at the junction of the moving and non-moving parts. Changes in triangulation edge lengths and area from frame 70 to 71 (Figure 2(a) and 3(a)), and from frame 70 to 76 (Figure 2(b) and 3(b)) agree with these observations. Notice that the fingerprint seems to be expanding vertically but compressing horizontally.
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(a) Illustration (not to scale). |
(b) Fingerprint. |
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Figure 1. Finger rotating over a flat surface. |
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(a) Interval of 1 frame. |
(b) Interval of 6 frames. |
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Figure 2. Measurements obtained from the relative variations in edge length. |
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(a) Interval of 1 frame. |
(b) Interval of 6 frames. |
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Figure 3. Measurements obtained from the relative variations in area. |
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