A Signal to Noise Optimization Algorithm for Speckle Interferometry Applications

Abstract : Optical Full Field Techniques (OFFT) are more and more utilized by mechanical laboratories. Among these methods, interferometry techniques (mainly composed of Speckle/Grating Interferometry or Speckle/Grating Shearography) are more difficult to use in a mechanical lab context, because of their sensitivity to external vibrations (except shearography), and because of the global lack of optical culture of mechanical engineers. Speckle-based methods are of great practical interest for the users, but their signal to noise ratio (SNR) is affected by the rigid body motion of the specimen. Here, the speckle decorrelation is minimized at local scale directly using the SNR. First, a shearography experiment is modeled to characterize the recorrelation procedure for a rigid body motion, a constant strain map and finally a high degree of localization. The mean noise level is found to be 6 times higher than a fully-correlated phase map for a 1 pixel speckle size. Last, a first application to a single-ply fabric composite lamina is shown. Resulting strain maps are of high quality with a very low spatial resolution (4 pixels). The local bending / global tension coupling effect is clearly put in evidence.
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Applied Mechanics and Materials, Trans Tech Publications, 2008, 13-14, pp.29-38. 〈10.4028/www.scientific.net/AMM.13-14.29〉
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https://hal-emse.ccsd.cnrs.fr/emse-00502174
Contributeur : Anna Fraczkiewicz <>
Soumis le : mardi 13 juillet 2010 - 13:04:11
Dernière modification le : jeudi 22 février 2018 - 13:06:06

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Jérôme Molimard, Raul Cordero, Alain Vautrin. A Signal to Noise Optimization Algorithm for Speckle Interferometry Applications. Applied Mechanics and Materials, Trans Tech Publications, 2008, 13-14, pp.29-38. 〈10.4028/www.scientific.net/AMM.13-14.29〉. 〈emse-00502174〉

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