Speckle Methods and Applications

TLDR: In this paper, a three-dimensional interference pattern formed by the interference of secondary, dephased wavelets scattered by an optical rough surface or transmitted through a scattered medium that imposes random phases of the wave.

Abstract: Speckle pattern is a three-dimensional (3D) interference pattern formed by the interference of secondary, dephased wavelets scattered by an optical rough surface or transmitted through a scattered medium that imposes random phases of the wave. The randomly coded pattern that carries the information about the object deformation provided to develop a wide range of methods, which can be classified into three broad categories: speckle photography, speckle interferometry, and speckle shear interferometry. Speckle photography is based on recording of objective or subjective speckle patterns, before and after the object is subjected to load. Digital speckle shear interferometry or digital shearography (DS) has been widely used for the measurement of the spatial derivatives of object deformation. The DS system has found a prominent application in aerospace industry for nondestructive testing of spacecraft structures. Microsystems such as micro-electro-mechanical systems and micro-opto-electromechanical systems combining micro-size electrical and mechanical mechanism are finding increasing applications in various fields.