Determination of surface contour by temporal analysis of shadow moiré fringes
A simple temporal analysis algorithm (phase scanning method) is proposed for 3-D surface profile measurement of a vibrating object based on shadow moiré technique. A grating is positioned close to a low-frequency vibrating object and its shadow is observed through the grating. The moiré fringe pa...
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| Main Authors: | , , |
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| Other Authors: | |
| Format: | Article |
| Language: | English |
| Published: |
2011
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| Subjects: | |
| Online Access: | https://hdl.handle.net/10356/91584 http://hdl.handle.net/10220/6706 |
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| Institution: | Nanyang Technological University |
| Language: | English |
| Summary: | A simple temporal analysis algorithm (phase scanning method) is proposed for 3-D surface profile measurement of a vibrating object based on shadow moiré technique. A grating is positioned close to a low-frequency vibrating object and its shadow is observed
through the grating. The moiré fringe patterns, generated by the interference of grating lines and shadow lines, are captured by a high-speed CCD camera with a telecentric gauging lens. Phase values are evaluated point by point using phase scanning method.
From the phase values of each point on the object, the high-quality surface profile of the
specimen at different instants of vibration can be retrieved. In this application, two specimens are tested to demonstrate the validity of the method, one is a spherical cap with height of 4 mm, the other is a small coin with unevenness of less than 0.2 mm. The
experimental results are compared with test results using mechanical stylus method. |
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