The Testing And Research Of Object’s Tiny Movement And Deformation Based On Digital Speckle

Digital laser speckle and the rapid development of computer technology havebrought unprecedented changes to optical measurement mechanics, and theimplementation of real-time digital speckle measure technology, making it widely usedin the actual measurements. There are many measure methods for tiny movement anddeformation of objects, the data more accurate, and the algorithm is also more and moreadvanced, but there are more and more high precision for small objects measurementrequest, it has become more and more urgent about how to measure objects moreefficiency with a variety of tiny movement and deformation.Digital speckle photography is a kind of effective method and be widely usedbecause of the simple experimental conditions and the characteristics of real-timedynamic measurement. In order to get more efficient numerical method, the highprecision measurement, and more applicable to the actual measurement when being outof the lab, this paper adopts the method of digital speckle photography as the researchobject, on the basis of analyzing the theory of digital speckle technology, the detailedresearch has been carried on architecture of digital speckle system, overall schemedesign and the use of the improved algorithm. Thus the theoretical analysis for specklegraph has been given, and a kind of spatial spectrum displacement has been put forward,using the composite of vibration amplitude subtraction mode and sub image and pixelprocessing method with the combination of a variety of ways, which have furtherimproved the accuracy of measurement results. In order to be more accurate whenmeasuring less than20microns deformation, a new algorithm has been put forward,which is to get two peak values from the new function constructed after the Fouriertransform to two exponential functions, the direct Fourier transform of deformationbefore and after pictures. In addition, a series of studies have taken on thesignal-to-noise ratio of the picture, laying the foundation for the measurement ofnon-rigid deformation.Adopting double speckle figure projection system of3D displacement is calculatedto locate space displacement, in order to get good position precision. By the space of the selected coordinate system the system measuring space displacement formula wasderived, it has been compared using the rotating way to get double speckle graphsimulation method, a CCD camera) with binocular CCD camera system spacedisplacement measurement results. They have their own advantages and disadvantages.Mechanical positioning has fast speed but inevitable mechanical error, while binocularCCD has accuracy higher result but long computing time.In real life, the improved algorithm is applicable to non-rigid deformationmeasurement, thus experiment system has been set up, and a large number of digitalspeckle measurement experiments have been carried on. Finally through the spacedisplacements, the experiment and research has been carried on about the rigid-bodytranslational displacement and micro Angle. Through experimental verification, thedigital speckle measurement system is effective and more accurate in this paper, whichhas laid the foundation for the further study of the deformation in order to study furtheron the digital speckle measure technology for applying to real life.