Computerized Displacement Data Analysis in Laser Speckle Photography

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Bibliographic Details
Title: Computerized Displacement Data Analysis in Laser Speckle Photography
Authors: Chitsaz, Bijan
Committee Members: Moslehy, Faissal A.
Summary: Laser speckle photography is an experimental technique which provides a non-contract means for direct measurement of in-plane displacements of objects subjected to different loading conditions. It requires a camera system to record two images of the object that are illuminated with laser light on a high resolution film. The double-exposure film (specklegram) is a permanent record of the displacement information of the object. Point-by-point analysis of the specklegram will yield the displacement data, but requires considerable time to complete the data reduction. An automated data analysis system is developed and described in this report. He-Ne laser and computer-controlled translation stages holding the specklegram represent the first part of the system. A linear diode sensor is used to digitize the generated fringe pattern. Finally, a microcomputer and a spectrum analyzer are used to perform the analysis. The system has been successfully applied to the computation of displacements of a cantilever beam. Comparisons to theoretical results indicate that the system is indeed a viable one and may be sued for a more complex displacement analysis.
URL: https://stars.library.ucf.edu/rtd/4818
Database: OpenDissertations
Description
Abstract:Laser speckle photography is an experimental technique which provides a non-contract means for direct measurement of in-plane displacements of objects subjected to different loading conditions. It requires a camera system to record two images of the object that are illuminated with laser light on a high resolution film. The double-exposure film (specklegram) is a permanent record of the displacement information of the object. Point-by-point analysis of the specklegram will yield the displacement data, but requires considerable time to complete the data reduction. An automated data analysis system is developed and described in this report. He-Ne laser and computer-controlled translation stages holding the specklegram represent the first part of the system. A linear diode sensor is used to digitize the generated fringe pattern. Finally, a microcomputer and a spectrum analyzer are used to perform the analysis. The system has been successfully applied to the computation of displacements of a cantilever beam. Comparisons to theoretical results indicate that the system is indeed a viable one and may be sued for a more complex displacement analysis.