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This paper presents a novel technique allowing time-dependent displacement of an object to be studied by continuously digitizing the speckle images using a high speed image acquisition system. Instead of generating fringe patterns, the displacement versus time for any point of interest can be studied. Therefore, the technique is equivalent to “many” massless and noncontact displacement sensors, which is particularly useful for vibration measurement.

Shearography is an optical technique developed for full-field measurement of surface deformation. It has since been accepted by industry as a practical nondestructive testing technique for evaluating the structural integrity of components and structures. Qualitatively, shearography reveals flaws from flaw-induced, anomalous deformation in the component under inspection, and quantitatively, shearography assesses the detected flaws through back-calculation from the anomalous deformation. This paper demonstrates that, with the use of multiple-frequency acoustical excitation together with the time-integrated shearographic recording technique, rapid and automated assessment of the integrity of adhesive-bonded composite structures can be realized in the actual plant environment.