Improved accuracy in slope measurement and defect detection using Fourier fringe analysis

Abstract This communication reports investigation undertaken towards measurement of slope and defect detection of bent plates (rectangular and circular) using moire deflectometry in conjunction with Fourier transform technique. For slope mapping, specimen is illuminated by collimated light from a laser. The back reflected light from the front surface of the specimen is incident on a set of two gratings placed in tandem, resulting in the formation of laterally sheared interferograms. The interferograms are recorded using a CCD (charge coupled device) camera. Direct phase measurement using Fourier transform method has been used for measurement of slope and detection of defects. The experimental setup is simple and the slope measurement and detection of defects are undertaken successfully in each case. Experimental results conclusively establish the viability of the technique. Good accuracy and precision in measurement have been achieved.

[1]  David R. Burton,et al.  A new model for measuring object shape using non-collimated fringe-pattern projections , 2007 .

[2]  Reena Disawal,et al.  Improved measurement characteristics in collimation testing using Lau interferometry and Fourier fringe analysis technique , 2014 .

[3]  Tilo Pfeifer,et al.  Phase-shifting Moiré deflectometry , 1995 .

[4]  F. P. Chiang,et al.  Dynamic moiré methods for the bending of plates , 1973 .

[5]  O. Kafri,et al.  Diffraction effects in moiré deflectometry: reply to comment , 1986 .

[6]  J A Quiroga,et al.  Improved phase-shifting method for automatic processing of moiré deflectograms. , 1998, Applied optics.

[7]  H. Tippur.  Simultaneous and real-time measurement of slope and curvature fringes in thin structures using shearing interferometery , 2004 .

[8]  Eryi Hu,et al.  Surface profile measurement of moving objects by using an improved π phase-shifting Fourier transform profilometry , 2009 .

[9]  P. Theocaris,et al.  Slope measurement by means of moiré fringes , 1965 .

[10]  W. Macy,et al.  Two-dimensional fringe-pattern analysis. , 1983, Applied optics.

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

[12]  Fu-Pen Chiang,et al.  Family Of Grating Techniques Of Slope And Curvature Measurements For Static And Dynamic Flexure Of Plates , 1982 .

[13]  Shashi Prakash,et al.  Automated collimation testing by incorporating the Fourier transform method in Talbot interferometry. , 2011, Applied optics.

[14]  G. Subramanian,et al.  A selective diffraction order based lens plane grating shearing interferometer for the study of bent plates , 1987 .

[15]  Vincent Pagneux,et al.  Experimental and theoretical inspection of the phase-to-height relation in Fourier transform profilometry. , 2009, Applied optics.

[16]  C. Caroubalos,et al.  Fast estimation of slopes of linear and quasi-linear structures in noisy background, using Fourier methods , 2007, Pattern Recognit..

[17]  Yang Song,et al.  Theoretical analysis for moiré deflectometry from diffraction theory. , 2009, Journal of the Optical Society of America. A, Optics, image science, and vision.

[18]  M. P. Kothiyal,et al.  Simultaneous measurement of out-of-plane displacement and slope using a multiaperture DSPI system and fast Fourier transform. , 2007, Applied optics.

[19]  S. Prakash,et al.  Measurement of slope of bent plates using phase shifted moiré deflectometry , 2012 .

[20]  Mitsuo Takeda,et al.  Fourier fringe analysis and its application to metrology of extreme physical phenomena: a review [Invited]. , 2013, Applied optics.

[21]  Ran Gao,et al.  An optical Fourier Transform spectrometer based on the Michelson interferometer with angle difference between two mirrors , 2015 .

[22]  Slobodan Mitrović,et al.  Refined fourier-transform method of analysis of full two-dimensional digitized interferograms. , 2003, Applied optics.