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Proceedings Paper

Finding small displacements of recorded speckle patterns: revisited
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Paper Abstract

An analytical expression for the bias effect in digital speckle correlation is derived based on a Gaussian approximation of the spatial pixel size and array extent. The evaluation is carried out having assumed an incident speckle field. The analysis is focused on speckle displacements in the order of one pixel, thus having no speckle decorrelation. Furthermore, sensitivity is a main issue wherefore we need speckles close to the pixel size, which means that speckle averaging becomes important, and that Nyquist’s criteria may not be fulfilled. Based on these observations, a new correlation method is introduced, which alleviates the need to know the expected shape of the crosscovariance between the original and the off-set recorded speckle pattern. This concept calls for correlating the crosscovariance with the auto covariance, which essentially carries information on the expected shape of the crosscovariance.

Paper Details

Date Published: 24 August 2015
PDF: 9 pages
Proc. SPIE 9660, SPECKLE 2015: VI International Conference on Speckle Metrology, 96601J (24 August 2015); doi: 10.1117/12.2195631
Show Author Affiliations
Steen G. Hanson, DTU Fotonik (Denmark)
Michael Linde Jakobsen, DTU Fotonik (Denmark)
Maumita Chakrabarti, DTU Fotonik (Denmark)
H. T. Yura, The Aerospace Corp. (United States)


Published in SPIE Proceedings Vol. 9660:
SPECKLE 2015: VI International Conference on Speckle Metrology
Fernando Mendoza Santoyo; Eugenio R. Mendez, Editor(s)

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