Alexander Spaett, Bernhard Zagar,
"Measurement of the coefficient of linear thermal expansion based on subjective laser speckle patterns"
, in Jürgen Beyerer, Thomas Längle: 5th International Conference on Optical Characterization of Materials (OCM 2021), KIT Scientific Publishing, Karlsruhe, Seite(n) 109 - 118, 3-2021, ISBN: 978-3-7315-1081-9
Measurement of the coefficient of linear thermal expansion based on subjective laser speckle patterns
Sprache des Titels:
5th International Conference on Optical Characterization of Materials (OCM 2021)
We present an improved processing of laser speckle intensity signals aimed at attaining spatial displacement resolutions well in the sub-pixel domain, which is necessary for measuring the minute displacements caused by thermal expansion of metallic specimens. The signal processing revolves around the cross power spectral density and the coherence function of two discrete signals, which allows for a continuously varying displacement result as opposed to a discretized, if determined in the spatial domain via the application of the cross-correlation function. The presented technique is then applied to estimate the coefficient of linear thermal expansion (CLTE) of a brass sample.