Research On Key Technologies Of Videogrammetric Measurement System

The videogrammetric measurement(VM)system can record and reflect the position,shape and motion state of the object,and has the advantages of non-contact,long distance,high precision and large amount of information and so on,which has been favored by researchers and ex perts both at home and abroad.This paper focuses on the key technologies of relative orientation,solving for external orientation elements,and homonymy matching in videogrammetric measurement systems as follows:(1)For the problem that the traditional camera parameters optimization method is difficult to reliably converge to the optimal solution under free shooting conditions,this paper proposes the boundary constraint function based on the penalty function optimization method.The method determines th e feasible region according to the accuracy of the initial value,and confines the optimization solution to the feasible region by constructing unique boundary constraint functions.(2)Relative orientation elements are used to restore the relative orienta tion of stereo pairs and are the basic parameters for videogrammetric measurement.This paper proposes a relative orientation optimization method with bounded constraints,the effectiveness of the optimization method is tested according to the number of coding points,the accuracy of initial value and the different cameras.Experiment show that the optimal solution can be quickly converged in the case of low initial value,which is more accurate than the result of the genetic optimization method.(3)The camera exterior orientation elements are the key parameters for achieving matching of homologous points and acquiring 3D coordinates.We first use the direct linear transformation method to solve the initial value,and then use the optimization method with bounded constraints to optimize the initial value.The optimization improves the accuracy of the exterior orientation elements,providing guarantee for the realization of multi-camera high-accuracy matching.(4)This paper studies and analyzes the existin g matching constraints method,and optimizes the implementation process and programmability of the matching algorithm based on the epipolar constraint.The program design is completed on the VS platform.The results of the non-coded point exact match are obtained,and the 3D coordinates of the feature points are successfully acquired.The practicality and effectiveness of the bound constraint function optimization method in videogrammetric measurement are verified.