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Proceedings Paper

Fresnel wavefront propagation model for shearography shape measurement
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Paper Abstract

This paper describes a new technique for modelling slope fringes in shearography using Fresnel wavefront propagation. Shearography is a full-field speckle interferometry technique usually used for displacement gradient and for shape measurement. One feature of shearography is that it uses a close to common path interferometer. This has the advantage of reducing sensitivity to environmental disturbances, but the disadvantage of a non-linear response. Previously one of the authors has used a ray tracing model of the fringe formation to improve the shape and slope measurement capabilities of shearography. The calculation involved was relatively time consuming as it required the calculation of the phase for each camera pixel individually. In this new Fresnel wavefront propagation model the approach is different. The system is modelled by propagation of the entire wavefront. This includes propagating the light through optical elements, such as a lens. This initial study has been for the formation of slope fringes in shearography using the source displacement technique. The advantages of this new technique are that it is easier to introduce optical elements and the effects of speckle noise into the simulation.

Paper Details

Date Published: 18 June 2007
PDF: 8 pages
Proc. SPIE 6617, Modeling Aspects in Optical Metrology, 66170Q (18 June 2007); doi: 10.1117/12.725985
Show Author Affiliations
Arun Anand, ITO Institut für Technische Optik, Univ. Stuttgart (Germany)
Institute for Plasma Research (India)
Roger M. Groves, ITO Institut für Technische Optik, Univ. Stuttgart (Germany)
Xavier Schwab, ITO Institut für Technische Optik, Univ. Stuttgart (Germany)
Giancarlo Pedrini, ITO Institut für Technische Optik, Univ. Stuttgart (Germany)
Wolfgang Osten, ITO Institut für Technische Optik, Univ. Stuttgart (Germany)


Published in SPIE Proceedings Vol. 6617:
Modeling Aspects in Optical Metrology
Harald Bosse; Bernd Bodermann; Richard M. Silver, Editor(s)

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