Tunable laser diode for absolute distance measurement
We propose an interferometric method for absolute distance measurement. This method uses the fact that the wavelength of a laser diode can be tuned continuously, by addition of an external cavity. The...
Theory of speckle displacement and decorrelation: application in mechanics
Proc. SPIE, Vol. 3479, 345 (1998);
doi:10.1117/12.316468
Online Publication Date: 16 May 2003
Conference Date: Wednesday 22 July 1998
Conference Location: San Diego, CA, USA
Conference Title: Laser Interferometry IX: Applications
Conference Chairs: Ryszard J. Pryputniewicz, Gordon M. Brown, Werner P. O. Jueptner
ABSTRACT
Miroslav Hrabovsky Palacky Univ. (Czech Republic) and Institute of Physics (Czech Republic)
Thispaper describes the theory of determination of small deformation tensorby means of the method, availing of statistical properties ofthe speckle field in an optically free space geometry orin a near image field. The small deformation tensor anda correlation function are briefly mentioned, and the main emphasisis aimed on theoretical derivation of the relationship between thecorrelation function of two speckle intensities, being recorded before andafter deformation. This results in the relationship theoretically enabling adetermination of all components of the small deformation tensor bymeans of a relatively simple optical arrangement in connection withcomputer and linear CCD detectors. Further, a compilation of allcompleted experimental results are briefly mentioned. An accuracy and sensitivityof this measurement methods are analyzed by theory of errors.As it flows from theory, the exact results at stressdeformation, body displacement and rotation depend in crucially upon thegeometrical arrangement of the optical system. The emphasis on theanalysis of accuracy and sensitivity of individual geometrical parameters ofassembly are given, with the aim to find an optimizedgeometry of experimental arrangement. The feasibility of an easy realizationin practice and most importantly achieving satisfactory results of measurementsare the important criteria. The conclusion presents some results obtainedat concrete measurement with proposed experimental assembly.