In-Plane Displacement Measurements Using Speckle Photographs of Holographic Images.
Final technical rept. Sep-Dec 74,
AIR FORCE FLIGHT DYNAMICS LAB WRIGHT-PATTERSON AFB OHIO
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In recent years, laser speckle photography has emerged as a viable tool for measuring small in-plane displacements. For example, the local displacement field near a tapered shank interference fit fastener has been measured using this new technique. In this report it is shown that speckle photographic data can be recovered from any double exposure holographic interferogram. A method for extracting in-plane displacement information from a high resolution photograph of a double exposure holographic image is presented and discussed. The technique involves generating a diffraction halo and Youngs fringes in the same manner used to recover data from a conventional specklegram.
- Test Facilities, Equipment and Methods