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Journal of Atomic, Molecular, and Optical Physics
Volume 2012 (2012), Article ID 976376, 6 pages
http://dx.doi.org/10.1155/2012/976376
Research Article

Speckle Cross-Correlation Method in Measuring Fine Surface Displacements

Optical Metrology Department, National Institute for Standards, Tersa Street, Haram, P.O. Box 136, Giza 12211, Egypt

Received 7 July 2012; Revised 27 October 2012; Accepted 27 October 2012

Academic Editor: Keli Han

Copyright © 2012 M. Bahrawi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Industrial applications need regular testing for the lifetime, movement, strength, and performance of manufacturing machines during production process. Since speckle photography is a simple economic technique, it is used in investigating object response under mechanical and thermal effects depending on the movement of the speckle patterns with respect to the deformation strength and direction. In the present work, the cross-correlation technique is used to analyze the speckle patterns by iterative method to define both values and directions of rigid body translation and expansion. In order to check the accuracy of the cross-correlation technique, the results are compared with the displacement values given by analyzing the Young's interference fringes resulted from the Fourier transformation of the speckle patterns. This noncontact technique is found to be accurate and informative depending on the stability and sensitivity of the optical system. This method of measurement is an effective tool in studying the hard cases of objects and machines under various effects.