Robust approach to regularize an isochromatic fringe map.

The computation of a continuous map of isochromatic fringe order from an isochromatic phase map or relative retardation based on a photoelastic fringe pattern is a difficult task, particularly when the direction of the principal stress is ambiguous. This happens in most experiments and introduces abrupt changes in the slope of the computed relative retardation map. We present a novel regularized phase-tracking method that at each pixel chooses the unambiguous relative retardation value. This unambiguous relative retardation map is wrapped, however the unwrapping is straightforward and fast using the already known techniques. With the presented method we have been able to process successfully complex experimental data with several isotropic points, high fringe density and low resolution, as is shown in a number of examples.

[1]  Eann A. Patterson,et al.  A robust approach to demodulating and unwrapping phase-stepped photoelastic data , 2005 .

[2]  K. Oguni,et al.  Stress field tomography based on 3D photoelasticity , 2008 .

[3]  Giovanni Petrucci,et al.  Phase shifting photoelasticity in white light , 2007 .

[4]  Steve Haake,et al.  2D and 3D separation of stresses using automated photoelasticity , 1996 .

[5]  Johan Anton,et al.  Modern Photoelasticity for Residual Stress Measurement in Glass: Residual Stress in Glass , 2008 .

[6]  Eann A. Patterson,et al.  Towards full field automated photoelastic analysis of complex components , 1991 .

[7]  A. Curtis,et al.  Measuring cell forces by a photoelastic method. , 2007, Biophysical journal.

[8]  J.-C. Dupré,et al.  Whole field determination of isoclinic and isochromatic parameters , 1999 .

[9]  David P. Towers,et al.  Automatic analysis of isochromatic and isoclinic fringes in photoelasticity using phase measuring techniques , 1995 .

[10]  Melania Paturzo,et al.  Investigation of optical birefringence at ferroelectric domain wall in LiNbO3 by phase-shift polarimetry , 2006 .

[11]  Juan Antonio Quiroga,et al.  Determination of isoclinics in photoelasticity with a fast regularized estimator , 2008 .

[12]  S. Beck,et al.  Streaming Birefringence - A Step Forward , 2008 .

[13]  Eann A. Patterson,et al.  A quantitative evaluation of fatigue crack shielding forces using photoelasticity , 2008 .

[14]  Zhenkun Lei,et al.  Study of shear transfer in Al/epoxy joint by digital photoelasticity , 2009 .

[15]  H. S. Lien,et al.  Separation of Photoelastic Principal Stresses by Analytical Evaluation and Digital Image Processing , 2009 .

[16]  Johan Anton,et al.  A Discrete Algorithm of Integrated Photoelasticity for Axisymmetric Problems , 2008 .

[17]  M. Ramji,et al.  Whole field evaluation of stress components in digital photoelasticity—Issues, implementation and application , 2008 .

[18]  J. Marroquín,et al.  Demodulation of a single interferogram by use of a two-dimensional regularized phase-tracking technique. , 1997, Applied optics.

[19]  J. A. Quiroga,et al.  Robust isoclinic calculation for automatic analysis of photoelastic fringe patterns , 2008, International Symposium on Laser Metrology.

[20]  Eann A. Patterson,et al.  Digital Photoelasticity: Principles, Practice and Potential , 2002 .

[21]  Eisaku Umezaki,et al.  Digitally whole-field analysis of isoclinic parameter in photoelasticity by four-step color phase-shifting technique , 2007 .

[22]  Gary Cloud,et al.  Optical Methods of Engineering Analysis , 1996 .

[23]  J A Quiroga,et al.  Phase measuring algorithm for extraction of isochromatics of photoelastic fringe patterns. , 1997, Applied optics.

[24]  Eann A. Patterson,et al.  A photoelastic analysis of crescent-shaped cracks in bolts , 2001 .

[25]  Eann A. Patterson,et al.  High Frequency Quantitative Photoelasticity Applied to Jet Engine Components , 2006 .

[26]  Eann A. Patterson,et al.  Use of phase-stepping with demodulation and fuzzy sets for birefringence measurement , 1995 .

[27]  J A Quiroga,et al.  Separation of isoclinics and isochromatics from photoelastic data with a regularized phase-tracking technique. , 2000, Applied optics.