Research On Key Technologies Of Dynamic 3D Scanning Based On Optical Tracking

3D scanning technology can scan and obtain the external structural features of space objects.For more complex structural shape objects,3D scanning technology can save a lot of manpower and material resources.At present,the vast majority of 3D scanning equipment obtains part of the point cloud data separately,and then obtains the complete data of the object through the point cloud registration.This kind of application process,because it does not solve the problem of dynamic scanning,not only makes its application scenarios greatly limited,but also the time consumption and accuracy loss of late registration affect its ease of use.In order to solve the problem that the traditional binocular vision three-dimensional scanning needs multiple scanning before registration,a dynamic three-dimensional scanning method based on optical tracking is proposed.The first part is the monocular optical 3D scanning system,which uses the laser stripe as the active light source to realize the 3D scanning function.The second part is the monocular optical tracking system,which realizes the calculation and tracking of the pose of the scanning equipment,and converts the point cloud data obtained from the scanning part to the tracking camera coordinate system in real time,so as to realize the real-time registration of the data in the dynamic scanning process.The experimental results show that this method can achieve dynamic scanning,and finally obtain the point cloud information of the object.The scanning accuracy is about 1 mm in the coordinate plane and 0.08 mm in the axis.The mean square error deviation of point cloud data obtained by scanning is [-0.0017 mm,0.0017mm].The RMSE between the actual point cloud data and the ideal point cloud data is 0.400524,and the STD is 0.28463.At the same time,compared with the traditional binocular vision 3D scanning method,the scanning time can be saved by 50%.The main tasks are as follows:(1)Research on dynamic 3D scanning model.Through the analysis of the traditional vision measurement model,whether it is monocular structured light measurement model or binocular vision sensor model,the scanning method has some limitations.The dynamic 3D scanning model based on optical tracking proposed in this paper is composed of monocular3 D scanning model and monocular optical tracking model,which realizes dynamic,efficient and fast 3D measurement.(2)Build a monocular optical scanning model.The main work in this part includes the accurate calibration of camera parameters and the calibration of line structured light parameters.In the accurate calibration of camera parameters,the circular pattern calibration target with directional feature structure is used to calibrate the internal and external parameters of the camera,and the distortion parameters of the camera are calibrated by cross ratio invariance.In the calibration of line structured light parameters,through the comparative analysis of more mature calibration algorithms,the calibration method suitable for this model is obtained.(3)Build a monocular optical tracking model.Through the pose calibration between the scanning camera and the tracking target and the conversion from a single image to the tracking target,the scanning camera can obtain the point cloud information of the scanned object.Through the dynamic scanning model based on optical tracking proposed in this paper,real-time conversion to the tracking camera coordinate system,dynamic 3D scanning is realized.