Measurement of Three-Dimensional Deformation Using Speckle Projection Method

摘要

Optical triangulation is a useful method that has been studied and utilized extensively. In optical triangulation, the directions of projection and the observation are different, so the patterns captured by CCD camera include information of the object surface profile. Based on the speckle projection, a measurement system to get the three-dimensional deformation of object is developed. With artificial random speckle projected to the object surface, two images before and after object deformation are recorded, respectively. In order to get the information of the deformation, digital image correlation method (DICM) is adopted. Furthermore, the calibration is introduced in detail, which is the procedure of great importance, because it determines directly the accuracy of measurement. Due to variable feature of the calibration coefficient along the x direction, this paper presents a new method to be competent for the calibration, that's segmented calibration method. Experiment is performed and good agreement is found with the proposed calibration. Dynamic measurement results based on such system are also presented in this paper.