Application of Electronic Shear Speckle Pattern Interferometry to Nondestructive Evaluation of Materials
电子剪切散斑在检测材料缺陷中的应用

With the rapid development in electronics and computer technologies, the traditional holographic interferometry has arrived at electronic speckle pattern interferometry (ESPI) and electronic shear speckle pattern interferometry (ESSPI) stages. ESPI and ESSPI not only can measure the surface deformation, but also have the advantages of real time, high sensitivity, non-contact and full field, etc. Consequently, they have led to a real opportunity for more and more applications in the industrial and scientific worlds. This paper introduced the basic principle of ESSPI first, and then presented an ESSPI image processing system about out-of-plane displacement developed by the authors in detail. The main functions of the system include ambiguity, sign of region, statistics of pixel, etc. Using the system, the ESSPI images were processed and the area of the defect was determined directly. The processed results for a sample with some known defect are well agreed with the actual defects. Therefor the present ESSPI image processing system is reliable.