Calibration And Registration Of Different-source And Non-coaxial Measuring Camera

The different-source and non-coaxial telephoto imaging measurement camera includes a visible light camera and a near infrared camera,and two cameras share a Cassegrain reflective optical system.The measuring camera is used for completing the measurement of the laser illuminator illumination precision through a vertical target.A visible light camera is used to capture moving targets,and a near infrared camera is used to take illumination lasers.The Cassegrain optical system of the measurement system has large aberrations and two camera are non-coaxial.Therefore,this thesis proposes the calibration and registration techniques for different-source and non-coaxial measuring cameras.The main research work of this thesis is as follows:(1)The imaging model of different-source and non-coaxial measuring camera is established,and its distortion type is determined.According to the camera calibration method of Zhang Zhengyou,the influence of perspective error is ignored because of the telephoto imaging characteristics of measuring camera.A camera calibration method for a telephoto imaging system is proposed in which the skewless constraint is zero in camera intrinsic parameters.The camera parameter solving model is established,and the intrinsic parameters,extrinsic parameters and distortion parameters of the two cameras are obtained by calculation,and the image optical distortion is corrected.(2)The coordinate transformation relationships of two camera image planes are analyzed,the registration model of different-source and non-coaxial measurement camera is established,the mapping relation of the different-source image is studied,and the registration method of different-source and non-coaxial camera is put forward.The camera registration matrix of the near infrared camera and the visible light camera is obtained by the normal equations method.(3)The high-precision detection method of center of the star point centroid and the cross center is studied.According to the telephoto imaging principle,the target calculation method for collimator simulating the finite imaging distance of visible light camera and near-infrared camera.Star plate and grid plate are used for camera calibration and registration respectively.The results show the reprojection error of visible light camera and near infrared camera calibration is 0.08 pixels and 0.25 pixels respectively.Camera registration axis consistency accuracy is 0.37 μrad.Meet the needs of laser illuminator illumination accuracy field test.