| Digital speckle correlation methods (DSCM) have been extensively used to accurately determine two-dimensional in-plane displacements and strains in both theoretic study and engineering measure.The work reported herein is concerned with the development of new DSCM, on which a stable, high-speed and accurate DSCM data processing system is built. And then the theory of DSCM and the excellence of the simulative speckle images are introduced.This paper study on measurement methods for DSCM, and basic principles and search methods of DSCM were described in detail.In the first, the advantages and disadvantages of search algorithm for DSCM at present has been summed up. It can reduce the running time and raise the precision to 0.01 pixels when the method of cross search was used to calculate the entire pixel displacement and the method iterative gradient was used to calculate the sub-pixel displacement. A user -friendly, easy-to-use, digital speckle-related measurement software was Programmed base on the above principle, which can survey of the basic conditions for the use of DSCM in scientific research and engineering. The software can accurately calculate the displacement, draw displacement, and product a simulate picture. At the same time has also used the simulation speckle plans verify the reliability of calculation and consistency of the results.Finally, the displacement, which come from the test on three bends and tensile of PMMA, were calculated by the software of DSCM has been prepared. The results show that, the algorithm can reach the actual requirements. |
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