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

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 profilometer.

[1]  Domenica Paoletti,et al.  Holographic contouring method: application to automatic measurements of surface deffects in artwork , 1991 .

[2]  Hsin-Chu Liu,et al.  Optical three-dimensional sensing by phase measuring profilometry , 1989 .

[3]  Fu-Pen Chiang,et al.  Contouring by moiré interferometry , 1991 .

[4]  Xianyu Su,et al.  A direct mapping algorithm for phase-measuring profilometry , 1994 .

[5]  Xianyu Su,et al.  Automated phase-measuring profilometry using defocused projection of a Ronchi grating , 1992 .

[6]  T Yatagai,et al.  Scanning moiré method and automatic measurement of 3-D shapes. , 1977, Applied optics.

[7]  K. Creath.  Phase-Shifting Speckle Interferometry , 1985, Optics & Photonics.

[8]  M. Takeda,et al.  Fourier transform profilometry for the automatic measurement of 3-D object shapes. , 1983, Applied optics.

[9]  C. Quan,et al.  Double-source holographic contouring using fibre optics , 1990 .

[10]  E Marom,et al.  Phase-only modulation with twisted nematic liquid-crystal spatial light modulators. , 1988, Optics letters.

[11]  Satoru Toyooka,et al.  Phase shifting common path interferometer using a liquid-crystal phase modulator , 1994 .

[12]  René Dändliker,et al.  Holographic Contouring Using Electronic Phase Measurement , 1985 .

[13]  D R Burton,et al.  Multichannel Fourier fringe analysis as an aid to automatic phase unwrapping. , 1994, Applied optics.

[14]  Huai Min Shang,et al.  A new method for generating and analysing digital speckle shearing correlation fringe patterns , 1998 .

[15]  Satoru Toyooka,et al.  Speckle-shearing interferometry using a liquid-crystal cell as a phase modulator , 1991 .