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Proceedings Paper

Mechanical measurement using multiplexing/demultiplexing of digital Fresnel holograms
Author(s): Pascal Picart; Eric Moisson; D. Mounier
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Paper Abstract

We propose a multiplexing/demultiplexing technique in digital Fresnel holography for the simultaneous measurement of two dimensional deformations. The spatial multiplexing uses the incoherent mixing of 2x2 coherent waves. The optical arrangement of the setup gives access simultaneously to the out of plane and the in plane component of the displacement field. For this, we use a twin polarizing Mach-Zehnder interferometer which produces the simultaneous incoherent addition of two holograms of the object. The digital holograms are reconstructed using the discrete Fresnel transform. Each object phase encodes the in plane and out of plane component of the displacement field vector. In order to exract the mixing of the 2D measurement, we use a spatial demultiplexing of the holograms. Its principle is based on the use of the spatial autocorrelation function. The spatial coordinate of one of its three lobes is used for the demultiplexing of the second hologram on the first. This numerical demultiplexing is based on the two dimensional Fourier transform and the application of the so called delay theorem. After demultiplexing, the sum of the two phase change gives access to the out of plane component and their difference to the in plane one. Experimental results dealing with the study of the mechanical behavior of composite materials are presented.

Paper Details

Date Published: 27 May 2003
PDF: 9 pages
Proc. SPIE 4933, Speckle Metrology 2003, (27 May 2003); doi: 10.1117/12.516666
Show Author Affiliations
Pascal Picart, Ecole Nationale Supérieure de d'Ingénieurs du Mans (France)
Eric Moisson, Ecole Nationale Supérieure de d'Ingénieurs du Mans (France)
D. Mounier, Ecole Nationale Supérieure de d'Ingénieurs du Mans (France)

Published in SPIE Proceedings Vol. 4933:
Speckle Metrology 2003
Kay Gastinger; Ole Johan Lokberg; Svein Winther, Editor(s)

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