In-plane-displacement measurement by speckle interferometry using virtual speckle pattern based on Carré algorithm

Dynamic deformation measurement with a large in-plane deformation is performed by using virtual speckle patterns. The virtual speckle pattern has been generally produced by using Fourier technology. However, it takes a long calculating time to produce a virtual speckle pattern under Fourier technology, because the method requires Fourier transform operation at each pixel of CCD. In the proposed method, virtual speckle patterns are produced by Carré algorithm without any operation by Fourier transform. As the results, it is confirmed that the calculating cost of virtual speckle patterns is improved remarkably, and that the new method also is almost equal to the ordinary methods in measurement accuracy.