Study Of Micro-Electronic Speckle Pattern Interferometry

Electronic speckle pattern interferometry (ESPI) is a modern optical measurement technique witch combines with laser, computer, CCD and image processing techniques. It has many advantages such as the nondestructive, the full-field, high precision. ESPI has been widely used in the fields such as measurement of rough surface, stress and strain analysis, vibration measurement and so on. In recent years accompanying the rapid growth of the nano-materials, measurement of material property parameters such as mechanical characteristics of microstructure, stress variation of surface, deformation becomes more and more important. To satisfy these challenges, micro-electronic speckle pattern interfermetry (Micro-ESPI) are being implemented.The main works of this paper are as follows:1) Four-steps phase shifting algorithm of the micro-electronic speckle interferometry is simulated by MATLAB, and the measuring error caused by step size variance is discussed.2) To satisfy the requirement of step distance of experimental phase shifter (Piezoelectric Ceramic), the phase shifter has been calibrated;3) The devices of Micro-ESPI have been built. The images of the speckle pattern before and after the deformation of silicon film are obtained respectively. The speckle pattern images are then filtered to remove the noise, and two dimensional phase unwrapping algorithm made by MATLAB is used to acquire the phase map of the measured object. Finally the deformation of the silicon film is obtained. The measuring accuracy is demonstrated by grating ruler.