The Digital Speckle Correlation Method Non-contact Dynamic Displacement And Vibration Measurement Technology Research

Dynamic displacement and frequency are the basic parameter in analyzing engineering structure and dynamic character of machine. Dynamic displacement and frequency are important monitoring amounts to ensure stabilization in construction and operation. This thesis aims at measure of low-frequency object, locates method on digital speckle correlation, develops non-contact measurement for displacement and frequency, achieves material advancement, grounds the product transformation of flash ranging mechanics.The thesis starts with literature survey, analyzes the requirement put forward in special dynamic condition, demonstrates research advancement in modern flash ranging mechanics, selects digital speckle correlation measurement, which has low requirement for measuring condition and object's surface photology condition, with fine resolution power, has prospect of non-contact measurement, develops the ZM-DF-1 dynamic displacement and frequency measurement system.During the thesis, author cooperates to complete the zoom lens, CCD, image sampling card hardware system. The application of the system in lab and field indicate that the optical performance and operation adjustment reach the requirement of image sampling. To solve the problem caused by the movement of speckle field we developed the software of ZM-DF-1, using conicoid fitting to realize sub-pixel correlation matching, using spectrum estimate to get fine precision (1.0%) with the image amount 30. Testing indicate the software matches the hardware. Because the image transmission rate is 25frame/second, the system is applied to measure displacement and frequencyof object operation at band width 0~12Hz.As deeper analyze and application research is needed, author using imitate image and true image in lab to test the correlation coefficient distributing, displacement and frequency of object, masters the infection of result precision by sign form, circumstance illumination, measure angle, measures distance and operation frequency of object. In the experiments the measure precision of displacement and frequency were demarcated.Finally, based on study experience, author mentions the consideration and advice in improvement and production transformation.