Research On Calibration Method Of Telephoto Lenses And Panoramic Vision System

The calibration of the visual system model is to determine the mapping relationship between 2D image and 3D space.It is the basis of vision measuremwnt.It has a board application prospect in space positioning,3D reconstruction and virtual reality.In view of the standard vision system,there are many effective calibration methods,but these calibration methods are not adaptable to the calibration of the long focal lenses vision system and the panoramic vision system.Unlike the standard vision system,the long focal lenses and the panoramic vision system have the system ill-condition and largedistortion filed of view respectively,which challenges the general calibration method.In this paper,the mapping relationship between the long focal lenses and the panoramic vision system are analyzed.A vision system calibration method based on matrix decomposition is proposed,which can effectively calibrate the visual system and have good generality.The main research work includes:(1)The vision system model and calibration method are analyzed in depth.Three classic vision system calibration methods are analyzed.A 3D target is made,and based on the Harris corner detection method,the automatic extraction of the target points is realized,which provides the condition for the calibration method in this paper.(2)A calibration method of vision system based on matrix decomposition is proposed.The method can simultaneously solve the internal and external parameters of the vision system.To a certain exrent,it avoids the coupling effect between the calibration parameters and improves the calibration accuracy.The validity of the method is verified by the calibration of standard visual system.(3)The ill conditioned characteristics of the long focal vision system are analyzed theoretically,and the difficulty of calibration is pointed out.The calibration method based on matrix decomposition is applied to realize the calibration of the long focal lenses.The advantages and characteristics of the method is analyzed and compared with Tsai calibration method and Zhang Zhengyou's calibration method in the aspects of backprojection error,generalization ability and condition number.(4)The calibration of the panoramic vision system represented by fisheye camera is completed.The nonlinear distortion characteristics of fisheye camera are analyzed theoretically,and by using evolutionary computation,the proposed method is improved and the panoramic vision system is calibrated.The distortion of the image is processed by calibration results and compared with Zhang Zhengyou calibration method.The backprojection error is calculated to verify the effectiveness of the method.