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Proceedings Paper

Dynamic laser speckle metrology with binarization of speckle patterns
Author(s): Elena Stoykova; Dimana Nazarova; Nataliya Berberova; Atanas Gotchev; Branimir Ivanov; Georgy Mateev
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Paper Abstract

Dynamic laser speckle analysis is non-destructive detection of physical or biological activity through statistical processing of speckle patterns on the surface of diffusely reflecting objects. This method is sensitive to microscopic changes of the surface over time and needs simple optical means. Advances in computers and 2D optical sensors forced development of pointwise algorithms. They rely on acquisition of a temporal sequence of correlated speckle images and generate activity data as a 2D spatial contour map of the estimate of a given statistical parameter. The most widely used pointwise estimates are the intensity-based estimates which compose each map entry from a time sequence of intensity values taken at one and the same pixel in the acquired speckle images. Accuracy of the pointwise approach is strongly affected by the signal-dependent nature of the speckle data when the spread of intensity fluctuations depends on the intensity itself. The latter leads to erroneous activity determination at non-uniform distribution of intensity in the laser beam for the non-normalized estimates. Normalization of the estimates, introduces errors. We propose to apply binarization to the acquired speckle images by comparing the intensity values in the temporal sequence for a given spatial point to the mean intensity value estimated for this point and to evaluate a polar correlation function. Efficiency of this new processing algorithm is checked both by simulation and experiment.

Paper Details

Date Published: 5 January 2017
PDF: 7 pages
Proc. SPIE 10226, 19th International Conference and School on Quantum Electronics: Laser Physics and Applications, 102260R (5 January 2017); doi: 10.1117/12.2262330
Show Author Affiliations
Elena Stoykova, Institute of Optical Materials and Technologies (Bulgaria)
Dimana Nazarova, Institute of Optical Materials and Technologies (Bulgaria)
Nataliya Berberova, Institute of Optical Materials and Technologies (Bulgaria)
Atanas Gotchev, Tampere Univ. of Technology (Finland)
Branimir Ivanov, Institute of Optical Materials and Technologies (Bulgaria)
Georgy Mateev, Institute of Optical Materials and Technologies (Bulgaria)


Published in SPIE Proceedings Vol. 10226:
19th International Conference and School on Quantum Electronics: Laser Physics and Applications
Tanja Dreischuh; Sanka Gateva; Albena Daskalova; Alexandros Serafetinides, Editor(s)

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