Experimental Mechanics @ Michigan State University
EM Basics: Fourier Analysis in PEA
§ Fourier analysis requires the collection of a large number of images, typical 90 for isoclinic map determination. § The methods used for determining isoclinic and isochromatic maps are different and have been developed by Morimoto et al^1 and Quan et al^2 respectively. § The grey-field polariscope developed by Lesniak et al^3 is not readily classified and falls between fourier processing and phase-stepping. § These techniques produce periodic distributions of isoclinic and isochromatic fringe orders. The latter maps usually require unwrapping. See Ramesh^4 for more details on digital photoelasticity and associated issues.
Morimoto, Y., Morimoto Jr, Y., Hayashi, T., 1994, ‘Separation of isochromatics and isoclinics using fourier transform’ Experimental Techniques, 18(5):13-18. Quan, C., Bryanston-Cross, P.J., Judge, T.R., 1993, ‘Photoelasticity stress analysis using carrier fringe and FFT techniques’ Optics & Lasers in Engineering, 18:79-108. Lesniak, J., Zickel, M., Bazile, D., Boyce, B., 1999, ‘Assessment of grey-field photoelasticity’, Proc. 5th Int. Conf. Experimental Mechanics, Montreal, pp.856-9. 4. Ramesh, Digital photoelasticity, Springer Verlag
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