Dehnungsmessung mit Laser-Speckles

Martin Wurm

Research output: ThesisMaster's / Diploma thesis

Abstract

In the course of this thesis two systems for strain measurement based on laser speck- les were examined. The two laser{speckles{sensors concerned were the laser{speckle{ extensometer, in short LSE, and the locally operating laser{speckle{strain{sensor, in short LSDS. The difference between the two systems basically lies in their optical confguration: the LSE uses two patterns of subjective speckles projected onto a single camera, the LSDS on the other hand images patterns of objective speckles of laser illuminated areas onto two cameras. A mathematical model for the LSE has been worked out and a digital signal processing algorithm has been derived from it. For the LSDS the model of Yamaguchi Ichiro was used employing the same algorithm as the LSE. In the course of this work the displacement for the line scan data derived from CCD- cameras were analyzed by the algorithm been implemented in Matlab in order to calculate the extension of the samples. The LSE measuring system already existing produced satisfying results in all the experiments. While inspecting the line scan data more closely it was found that the CCD{chip used showed an offset error difference for even and odd pixels. Though this irregularity did not have too much of an in uence on the experiments, it should be taken into consideration as a potential source of error in the future.
Original languageGerman (Austria)
Publication statusPublished - Jun 2005

Fields of science

  • 102003 Image processing
  • 202024 Laser technology
  • 202037 Signal processing
  • 203016 Measurement engineering
  • 205016 Materials testing

JKU Focus areas

  • Mechatronics and Information Processing

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