| The ship-borne integrated mapping system highly integrates advanced sensors such as satellite positioning receiver,laser scanner,multi beam transducer,inertial measurement system and camera and so on,organically coordinating the time synchronization,operational response,data transmission and storage of each sensor via the core controller to form a three-dimensional space measurement system,which can can realize seamless measurement on water and under waterIn order to splice the point cloud data collected by multi beam bathymetric system and laser scanner,it is necessary to calibrate the relative position and attitude of multi beam transducer,inertial measurement unit and laser scanner.In this paper,the application of dual camera system in the calibration of Ship-borne integrated mapping system is analyzed based on the theodolite measurement system.In this paper,combined with the close range photogrammetry technology,a dual camera system is constructed,The self calibration method is selected to calibrate the dual camera system.According to the principle of double image stereo analytic measurement,the coordinates of the point to be measured are calculated,and the measurement accuracy of the dual camera system is evaluated.The practicability and reliability of the dual camera system are verified by the application experiment of the dual camera system.The outlines of this thesis are as follows:(1)The indoor 3D camera calibration field is selected as the camera calibration control field;the theodolite measurement system is used to obtain the control point coordinates of the calibration field;the target image acquisition technology of the dual camera system is summarized;the hough transform method is selected to identify and extract the control points in the photo;Ten parameter model is used to calculate the distortion parameters of camera;and the camera calibration results are compared with the automatic aerial survey software MAP-AT,the comparison of calibration results shows that the results of camera calibration program are reliable.(2)The hardware selection and integration of the dual camera system;the binocular stereo matching is completed by using the same image points;the spatial coordinates of the target point are calculated by the projection coefficient method for space forward intersection and the accuracy evaluation is carried out.By comparing and analyzing the coordinates of the mark points of the calibration field directly measured by the theodolite measurement system,the accuracy of the inspection point obtained by back projection is within 1.5 mm.According to the model of Seven parameter bursa,a coordinate conversion program is developed to calculate the relative position relationship of sensors in the mobile mapping system.And compared with A-xyz coordinate conversion module of industrial measurement system software,the results obtained by the two methods are consistent.(3)This paper summarizes the calibration technology of the theodolite measurement system to the ship-borne integrated mapping system in water and underwater.The dual camera system is used to calibrate the sensors of the ship-borne integrated mapping system in water and underwater,and the spatial registration between multibeam and inertial measurement system is completed.By comparing and analyzing the measurement results of the sensors of different combinations of ship-borne integrated mapping system in water and underwater,the difference of translation parameters between sonic coordinate system and IMU coordinate system is within 2mm,and the difference of rotation parameters is within 0.3°,the reliability and practicability of the dual camera system are verified. |
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