Shearography Testing

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Shearography is an interferometric imaging method used to detect surface and subsurface defects and anomalies on a wide variety of composite structures. Shearography is done by using a combination of coherent monochromatic laser light, shearing optic, CCD camera, image processor and a stressing technique. There is two basic types of shearography, the first being subtraction/correlation shearography and the latter which is phase stepping shearography. With subtraction/correlation shearography the image is formed by illuminating the test article with the laser interferometer (laser light/shear optic) which creates a reference image containing a unique speckle pattern.