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Proceedings Paper

PIV: comparison of three autocorrelation techniques
Author(s): C. H. Westergaard; Preben Buchhave
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Paper Abstract

Three ways of implementing the 2-dimensional autocorrelation function (ACF) used for the extraction of displacement information in particle image velocimetry (PIV) records have been compared. The three methods are: (1) Numerical computation by means of two consecutive FFT algorithms directly from the digitized image, (2) a hybrid method by which an optical Fourier transform first forms the spatial power spectrum of the image, after which the ACF is computed by a numerical FFT (this method is usually known as the Young's fringe method) and (2) an all-optical correlator. These three methods are compared in terms of resolution and 'quality of data', a term covering signal-to-noise and detectability considerations. In spite of the fact that three methods in principle carry out the same underlying mathematical operation the resulting ACFs may look very different. However, as it turns out, the differences may be explained by artifacts characteristic of the practical implementations, and when these differences are taken into account, the three methods are seen to perform quite similarly.

Paper Details

Date Published: 6 August 1993
PDF: 7 pages
Proc. SPIE 2052, Fifth International Conference on Laser Anemometry: Advances and Applications, (6 August 1993); doi: 10.1117/12.150548
Show Author Affiliations
C. H. Westergaard, Technical Univ. of Denmark (Denmark)
Preben Buchhave, Technical Univ. of Denmark (Denmark)

Published in SPIE Proceedings Vol. 2052:
Fifth International Conference on Laser Anemometry: Advances and Applications
J. M. Bessem; R. Booij; H. W. H. E. Godefroy; P. J. de Groot; K. Krishna Prasad; F. F. M. de Mul; E. J. Nijhof, Editor(s)

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