Electronic Speckle Pattern Interferometry And Displacement Measurement

Optics was in the physics an ancient application stronger foundation discipline, optics origin should trace the ancient times time (our country Spring and Autumn Period Warring States time). The afterwards more than 2,000 year long year constituted optics development germination period, it is in optics history section of slow advances ages. Electronic Speckle Pattern Interferometry (ESPI) is an important branch of optical measurement techniques. Speckle techniques make use of laser speckles formed in space or artificial speckles deposited on the specimen surface to monitor displacement or to carry out deformation measurement. In the past three decades, in addition to the study of the inherent properties of laser speckle fields, various speckle measurement techniques are gradually developed and widely applied in different fields.Electronic speckle pattern interferometry (ESPI), which uses fringe analysis for nondestructive deformation field measurements, has become an important technique. The method has many advantages of the whole-field measurement, the simple optical road, the easy modulation and the low demand for environment.By the widespread application to the automobile, is guarded against false, domain in the and so on commercial measurement,machinery,construction,water-conservation,electric-appliance,astronomy, aerospace, weapon industry, information processing, surface roughness, three dimensional face shape survey .In this dissertation, Electronic speckle pattern interferometry and displacement measurement are detailedly discussed. The main contents are described as the following:1. Reviewed has Electronic speckle pattern interferometry (ESPI) the discovery, the development, the classification and the application. Begins from the light interference survey, successively introduced the ESPI, the characteristic and the merit, the prospects for development, the method of Speckle Pattern Interferometry measurement.2.Principle of the phase measurement and FTM methods are introduced. The principle, the method and the arithmetic of the phase-shifting technique is specially introduced.The ESPI stripe chart frequency range filter method, analyzed has dispersed the picture the characteristic.3. Summarized the Displacement Measurement several methods.A method about the isolation of two-dimensional displacement by using one phase map is presented. When the typical ESPI is used for displacement measurement, a mixed phase distribution of deformation can be measured. If the deformation of the object is symmetrical, two components of deformation can be obtained by image processing. A typical experiment using a three-point-bending is completed. The experimental results prove the correctness of the method. The method presented does not only keep the advantages of simpleness, stability and applicability, but also obtain the in-plane displacement and out-plane displacement simultaneously.