Determination of surface contour by temporal analysis of shadow moiré fringes
Tay, Cho Jui
Date of Issue2004
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.
DRNTU::Science::Physics::Optics and light
This is the author created version of a work that has been peer reviewed and accepted for publication by Optics Communications, Elsevier. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [DOI:http://dx.doi.org/10.1016/j.optcom.2003.11.035].