Non Destructive Testing Using Temporal Phase Evaluation in Speckle Interferometry

A novel nondestructive testing (NDT) method where measurement of large object deformations using temporal evolution of the speckles in speckle interferometry is reported. Basic principle of the method is continuous object deformation is introduced and the fluctuations in the phase of the speckle as intensity modulation is recorded. Acquiring a large number of frames of the object motion the phase data for the whole object deformation is then retrieved by Fourier-transformation technique. The method is capable of measuring deformations of over 100 microns for in-plane and out-of-plane with speckle interferometry and over 500 μm for speckle shearing interferometry. We discuss the NDT results obtained with the three methods and make some relative comparisons of each of them.