Research On Multi-view 3D Stitching Measurement Technology Based On Structured Light

The three-dimensional(3D)measurement based on structured light is a key research topic in reverse engineering.Because of its non-contact,large measuring surface,high speed and easy information processing,it has been widely used in machine vision,virtual reality,intelligent manufacturing and other fields.However,this method has a disadvantage: when the field of view measured from a single perspective is limited and the complex structure of the object will cause local information to be blocked,it is impossible to obtain the overall 3D shape data of the object to be measured from a single perspective.Therefore,the research of 3D data splicing measurement method has become a hot spot.The purpose of this thesis is to study the multivision 3D splicing measurement technique based on structured light,and to improve the performance of the fringe projection technique in panoramic 3D measurement.A series of researches are carried out on the measurement system,calibration,phase shift method and data splicing method:1.The traditional 3D measurement system of structural light and the improved 3D measurement system are studied.The phase-height formula is improved by studying the system parallelism constraint.This paper introduces the basic principle of multi-frequency time phase unrolling method,and finally proves the effectiveness of the algorithm and the advantages of the improved system.2.A fast stitching method based on verticality calibration using three marker points is proposed.By applying a verticality calibration constraint to the measurement system and then improving the traditional three-marker method,the method greatly improves the splicing speed of the three-dimensional point cloud shape on the premise of ensuring the accuracy.Finally,a comparative experiment shows that: From the perspective of data splicing error,the proposed method is between quaternion method and singular value decomposition least square method.From the perspective of data splicing speed,the proposed method is far superior to the two methods.3.A novel method of rotating axis calibration in panoramic 3D shape measurement based on turntable is proposed.The rotation axis vector of the turntable is obtained by the auxiliary camera,and then the position transformation relation between the multi-viewpoint coordinate systems is obtained.Finally,the 3D morphologies of multiple perspectives were measured by the fringe projection system,and the rotation registration was completed according to the pose transformation relationship.This method solves the discrete error problem of space points in the traditional calibration method of turntable,has a high precision of calibration of rotation axis vector,and has a good effect of measurement and registration for complex targets.