AUTOMATIC-ANALYSIS OF 3-DIMENSIONAL DISPLACEMENT FIELD USING ESPI

Electronic speckle pattern interferometry (ESPI) has been used to stud y the in-plane and out-of-plane displacements of the object. In order to improve the accuracy, a Fourier filtration algorithm has been used to remove the speckle noise and get the holographic-quality ESPI fring e pattern. The processing steps of this method are described in detail in this paper. In addition, a phase shifter, which is easily used wit h simplified structure and high stability, is also presented. It can b e applied to various coherent arrangements in experiments to obtain ph ase shifted fringe patterns. Experiments of determining the 3D displac ement field of a circular fixed plate with a uniform load have been ca rried out using these methods. The results presented in this paper ind icate that the accuracy of this method is satisfactory. Copyright (C) 1996 Elsevier Science Ltd.