The Study Of 3D Digital Image Correlation Method Using Single Camera

With the progress of science and technology,people have higher and higher requirements on the quality of various structures,which also promotes the development of technology applied to the measurement of various structures.For common wood and mechanical structures,the traditional measurement methods are like displacement meter,strain gauge,dial gauge and other instruments.However,in practical use,these measurement methods have certain limitations.The measurement results are mostly approximate deformation in single point and single direction,which cannot effectively reflect the overall variation of the deformation structure.Digital image correlation method is a new optical measurement technology,which can realize non-contact measurement and high-precision full-field measurement of structure.However,in practical engineering application,digital image correlation technology has some limitations.The traditional 3D digital image correlation equipment has small shooting field and complex equipment,and the camera calibration process is complex,so the practical application is more limited.Therefore,this paper studies the single-camera 3D digital image correlation measurement system and the camera self-calibration method,and makes a comparative analysis of the experimental results,which can better realize the experimental measurement requirements.This paper mainly aims at practical engineering application.The content and results of this paper include the following parts:(1)The realization mode of single camera binocular measurement is studied,and the structural parameters of the four-plane mirror auxiliary system and the arrangement mode of virtual camera are analyzed.(2)The theoretical knowledge of camera imaging,the basic principle of camera calibration and the camera imaging model were studied,and a camera calibration method combining digital speckle method and zhang zhengyou's calibration principle was proposed and verified by experiments.(3)Based on the principle of digital image correlation matching and binocular vision 3D reconstruction,the 3D reconstruction program was written with Matlab software according to the 3D coordinate solving algorithm,and the 3d reconstruction experiment of the sphere surface was carried out.(4)The single-camera 3D digital image correlation measurement system is constructed,and the rigid body translation and off-plane displacement experiments of the cylinder are carried out with the system.The reliability of the system is verified by analyzing the calculation results.