Key Techniques Of Two-Dimensional Speckle Image Correlation Detection

With the dramatic development of industry in the whole world, the degree of precision and automation in each field is increasing. High-techs such as real-time measurement and monitoring techniques with high-precision and non-contact are widely applied in aviation,aerospace and other advanced fields. A system that can do quick measuring and monitoring precisely in the scene is badly in need in material property analysis, docking with the space station, airplane assembly and automotive body of reverse engineering, etc. Thus, this essay studies digital speckle correlation method and its key technologies which have a wide prospect in visual measurement industry.At the first, by setting up a theory model of digital speckle relating detecting technology,we will do a detailed contrastive analysis and research from aspects like precision, sensibility and efficiency in key techs such as correlative coefficient, searching mode and sub-pixel location, etc. It enables us to compare the advantages and disadvantages and developing potentials of different techniques. Then we will get a digital speckle image by the model.Through the analogue tests, we may confirm the approximate calculating parameters such as the speckling size, the optimal matching and calculating window and the most efficient way to test the calculating modes of digital speckling measuring. In order to minimize the influence of illumination intensity on the accuracy of measurement, we will, by analyzing with error theory, figure out the relationship between errors and illumination intensity and wave number.In this way, we can make sure how illumination conditions will influence the digital speckling correlative technique measurement and get the best illumination condition for digital speckling correlative calculation. To solve the problem of the loss of accuracy in measurement,we will bring in a coded target to get a rough target image. By calculating, we will get a corrected model and then the corrected speckling image will be recovered. This essay will prove that the quick correcting technique is effective and feasible.This essay will expound the development situation of current digital speckling correlative technology and its future study direction and deeply analyze the short-comings and advantages of this technology from both theory study and actual application. Key techs such as the illumination condition and image correction based on the influence of coded target on digital speckling correlative measurement will also be studied.