Displacement Measurement Based On The Combination Of Digital Speckle Correlation And Optical Flow And Phase Singularity

Micro-displacement measurement is an important field in optical measurement,it can be applied to engineering on-line detection,precision equipment processing,cell biometric and other different fields,the level of micro-displacement measurement technology directly affects the development of technical level in various fields.There are many ways to measure micro-displacement,but with the development of technology,measurement methods also need to be improved.In this paper,we mainly study and improve the method of micro-displacement measurement,the main contents are summarized as follows:1.In this paper,we study the basic theory of optical flow field,and clarify the basic equation of optical flow.Then we introduce the time dimension and get the new equation of optical flow.After this formula is transformed,we obtained the relation between the motion field,fringe frequency and out-of-plane deformation phase.We measured the horizontal and vertical displacement of the field according to the digital speckle correlation.Based on the window Fourier transform,the fringe frequency can be obtained,and the out-of-plane deformation phase can be obtained.The experimental results are compared with the theoretical values by simulation experiments,and the feasibility of the method is demonstrated.2.In this paper,the basic theory of wavelet transform is studied,and the morlet wavelet is used as the polarization analysis ability of the wavelet basis function to construct the phase singularity point with zero phase.The displacement is calculated according to the distance between the corresponding phase singularities before and after loading deformation.The simulation results show that the method is suitable for in-plane micro-displacement measurement.3.In view of the wavelet transform of the speckle image that is formed after loading out-of-plane deformation,the phase singularity distribution after the singular phase is scattered.We use the basic algorithm based on speckle correlation and optical flow field to deal with scattered phase singularity points.Simulation experiments show that there are some correlations between the calculated results and the theoretical values in the local area.the correlation between two-dimensional optical flow and out-of-plane displacement is provedagain.