Micro-Deformation Measurement Using Digital Speckle Pattern Interferometry

Micro-deformation measurement plays an important role in the analysis of material property, the reliability of components and the inspection of product quality. It is traditionally implemented by strain gage transducers, but it can't realize the non-contact whole field measurement. To overcome the disadvantage, the measurment method based on speckle pattern interferometry is often used. The method which relates to computer image processing and machine vision technology has the advantage of simple structure, high-precision, and can carry out whole field and non-contact measurement.This paper systematically studies digital speckle pattern interferometry (DSPI) for micro-defromation measurment, which involves the theory of the speckle, and the optical path system configuration for out-plane and in-plane deformation measurement, the extraction algorithms of the speckle pattern skeleton lines, the improvement techniques of high quality peckle pattern image a cquisition and the verification of the measurement feasibility. In the last sections, the experimental setups for out-plane and in-plane deformation measurement are builted up. Based on the experimental setups, the stress deformation measurement of aluminum and thermal deformation measurement of mechanical gear are achieved.