Shape identification using phase shifting interferometry and liquid-crystal phase modulator

✍ Scribed by C.J Tay; C Quan; H.M Shang

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 180 KB
• Volume: 30
• Category: Article
• ISSN: 0030-3992
• DOI: 10.1016/s0030-3992(99)00010-9

✦ Synopsis

A phase shifting technique using a Michelson interferometry system is presented and applied to surface contour measurement. Hyperbolic fringes are produced by the interference of two spherical wavefronts expanded from a beam expander. The fringe pattern is projected on an object surface and the deformed grating image is captured by a CCD camera for subsequent analysis by a PC. Phase variation is achieved by a liquid-crystal device incorporated in the Michelson interferometry system. Results obtained using the proposed method for objects of various shapes and sizes compared well with those from a conventional pro®lometer.