Research On The Simulation Modeling And Displacement Measurement Algorithms Of Digital Laser Speckle Image

Displacement measurement using digital laser speckle is a non-destructive and full-field measurement technique with coherent light incident on optical rough surfaces. The method has the advantages of real-time processing, simple-structure, no necessary of smooth surfaces, non-contact, full-field, etc. With the rapid development of digital image technique, laser technique and integrated circuit technique, the technique of displacement measurement using digital laser speckle is also developing quickly in terms of processing speed, the size of the device and the creativity of algorithms. This technique is being gradually applied to various areas such as vibration detection, displacement measurement, strain gauge, medical diagnosis, etc.After the careful study, this thesis gives an effective and available model of the dynamic laser speckle field. Several novel displacement measurement algorithms using digital laser speckle are put forward with their principles, approaches, the result of the algorithms, and their separate traits. To sum up, the main innovation and creative points are as follows:(1) A dynamic laser speckle model based on Gaussian correlation random surfaces is established. In this model, the computational simulation of the speckle field can be produced by a kind of reflectional surface, i.e., the Gaussian correlation random surface. The dynamic speckle image libraries with different speckle size, brightness, noise level and displacement can be got, which provides a god aid in our research of speckle characteristic and the experiments of displacement measurement.(2) A new displacement detecting method using digital speckle images based on Fast Fourier Transform, the phase comparison method, is presented. The method can accelerate the measurement, and compute the sub pixel displacement of the speckle image without interpolation. Compared with the common DSCM (Digital Speckle...