Measurement of curvature and twist of a deformed object using digital holography.

Measurement of curvature and twist is an important aspect in the study of object deformation. In recent years, several methods have been proposed to determine curvature and twist of a deformed object using digital shearography. Here we propose a novel method to determine the curvature and twist of a deformed object using digital holography and a complex phasor. A sine/cosine transformation method and two-dimensional short time Fourier transform are proposed subsequently to process the wrapped phase maps. It is shown that high-quality phase maps corresponding to curvature and twist can be obtained. An experiment is conducted to demonstrate the validity of the proposed method.

[1]  A Finizio,et al.  Whole optical wavefields reconstruction by digital holography. , 2001, Optics express.

[2]  F. P. Chiang,et al.  An optical method of generating slope and curvature contours of bent plates , 1979 .

[3]  C. J. Tay,et al.  Multiple-image shearography: a direct method to determine curvatures. , 1995, Applied optics.

[4]  M. P. Kothiyal,et al.  Simultaneous measurement of slope and curvature with a three-aperture speckle shearing interferometer. , 1984, Applied optics.

[5]  Fook Siong Chau,et al.  Direct measurement of curvature and twist of plates using digital shearography , 2003 .

[6]  Cheng Liu.  Simultaneous measurement of displacement and its spatial derivatives with a digital holographic method , 2003 .

[7]  E. Cuche,et al.  Digital holography for quantitative phase-contrast imaging. , 1999, Optics letters.

[8]  Qian Kemao,et al.  Two-dimensional windowed Fourier transform for fringe pattern analysis: Principles, applications and implementations , 2007 .

[9]  Rajpal S. Sirohi,et al.  A holographic speckle shearing technique for the measurement of out-of-plane displacement, slope and curvature , 1986 .

[10]  Chandra Shakher,et al.  Information reduction using lensless Fourier transform digital composite holography , 2008 .

[11]  M. P. Kothiyal,et al.  Talbot interferometry in noncollimated illumination for curvature and focal length measurements. , 1992, Applied optics.

[12]  B Ströbel,et al.  Processing of interferometric phase maps as complex-valued phasor images. , 1996, Applied optics.

[13]  P. Rastogi.  Visualization and measurement of slope and curvature fields using holographic interferometry : an application to flaw detection , 1991 .

[14]  A. K. Tieu,et al.  Simultaneous measurement of pure curvature and twist distribution fields by a five-aperture shearing and two-fourier filtering technique. , 2000, Applied optics.

[15]  Ichirou Yamaguchi,et al.  Phase-shifting digital holography , 1997 .

[16]  P. Rastogi,et al.  Measurement of curvature and twist of a deformed object by electronic speckle-shearing pattern interferometry. , 1996, Optics letters.

[17]  Y. Y. Hung,et al.  Image-shearing camera for direct measurement of surface strains. , 1979, Applied optics.

[18]  M. Takeda,et al.  Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry , 1982 .

[19]  Siew Lok Toh,et al.  Direct determination of second-order derivatives in plate bending using multiple-exposure shearography , 1994 .