Vibration analysis by digital speckle pattern shearing interferometry

Digital speckle pattern shearing interferometry is described as a robust measuring method due to its simple optical setup and the insensitivity against ambient noise. It has been used in industry for nondestructive testing and strain measuring. This paper explores the possibilities for vibration analysis using digital speckle pattern shearing interferometry. The measuring device performing both time-average and stroboscopic methods is described. The time average digital speckle pattern shearing interferometry in conjunction with the stroboscopic technique is suited well for both qualitative and quantitative vibration analyses. The determination of dynamic deformation and strain fields from the phase map of shearogram is demonstrated, and some preliminary results are shown.