Research On Three-dimensional Measurement Technology Of Binocular Vision Based On Coded Structured Light Projection

Three-dimensional imaging technology is a hot research field at present.Among the many methods proposed,the method of scanning and reconstructing the surface of an object using structured light has received more and more attention.3D reconstruction of projection structure light has many advantages,such as high accuracy,non-contact,fast detection speed,simple operation,etc.It is being applied more and more widely in industrial scenes.When a single-objective structured light system faces an object with a complex surface or a stepped or steep surface,it can not reconstruct a complete object surface due to occlusion problems.Binocular or multi-objective projection structured light systems can effectively solve the problems encountered by monocular systems,but also introduce new problems,such as the need to solve the calibration of multi-eye systems and the problem of multiple point clouds fusion.In this paper,the measurement principle of binocular structured light system is introduced in detail,including the coding and decoding technology of projection pattern,the calibration of parameters in system model,the generation and fusion of point clouds,etc.By analyzing the pattern coding and decoding strategy,it is decided to adopt Gray code coding,which can significantly improve the reliability of decoding.In the calibration of the projector,the projector calibration is converted into a mature camera calibration by a local homography transformation method,which greatly improves the accuracy of the projector calibration.In the last part of point cloud reconstruction,according to the characteristics of diamond-shaped projection devices,an improved scheme of three-dimensional point cloud reconstruction using triangular method is proposed,which effectively solves the deformation problem of point cloud reconstruction using triangular method.Then,based on the above principle,a set of binocular structured light 3D measurement system was developed,which can be used to reconstruct 3D complex surfaces.The hardware composition of the system is relatively simple,consisting of a projector and two cameras.When performing 3D reconstruction,the two subsystems(two projectors-camera pairs)are actually reconstructed by 3D point cloud respectively,and then the coordinates of right point clouds and left point clouds are fused.The experimental results show that the system's repeated relative measurement error is 0.6%when the working distance is 800 mm,which can effectively reconstruct thethree-dimensional shape of the measured object.