Study Of 3D Computer Vision For Photoelectric Theodolite Tracking Aircraft

The measuring images of aircraft tracked by photoelectric theodolite, record the various events and attitudes information of the aircraft during the motion process: such as space position, moving trajectory, moving speed, moving acceleration and pitch, yaw, roll changes. However, make the aircraft as a particle in traditional image process of electro-optical tracking, can not obtain the 3D attitudes information, so the shape and attitude information of the aircraft is discarded. The study of 3D computer vision for photoelectric theodolite tracking aircraft carried out in this dissertation, is to fully acquire the hidden information exist in the image by the optical theodolite tracking data, not only the aircraft movement information, but also the aircraft's 3D attitudes. Base on that, the aircraft's flight performance can be analyzed, judged, evaluated and validated, or it plays a corresponding role in test analysis, incident identification, training evaluation, flight control system testing and new model's designing.In order to achieve those purposes, this dissertation mainly includes three aspects: The first is to solve the moving trajectory and motion parameters of aircraft during the process of being tracked and measured, based on photoelectric theodolite tracking data; The second is to solve the aircraft's 3D attitudes based on the tracking images and data; The third is to establish the corresponding simulation model, according to tracking and measuring time nodes associated with the aircraft moving trajectory, motion parameters and 3D-attitude parameters, to drive the prebuilt aircraft's 3D model run in computer simulation environment, and restore the entire process of the aircraft being tracked and measured. First of all, under the condition of single-theodolite tracking and two-theodolite intersection tracking, the basic formula of the aircraft's space location are built, according to the measurement principle of photoelectric theodolite. Depending on that, the transfer relations among the photoelectric theodolite coordinate measurement system, the image coordinate system, the geocentric coordinate system and the launch coordinate system is given. Then dentermine the aircraft's space position by shape center(or weight center) tracking measurement, and using polynomial curve fitting method to obtain the moving trajectory equations along X, Y, Z three directions in a certain coordinate system. The first-order derivative equations of the trajectory equations are exactly the velocity equations, and the second-order derivative equations of the trajectory equations are exactly the acceleration equations. The accuracy analysis of moving trajectory, velocity and acceleration equations are carried out. After that, put forward the direction vector method of angle bisector lines for measuring the aircraft's 3D attitudes on the basis of exist methods. The aircraft's measuring images intersection tracked by two theodolites, through the process of image preprocessing, edge detection, feature information extraction, the direction of the wing edge characteristic line vector solving, direction vectors of two angle bisector lines solving, the pitch, yaw and roll of aircraft's 3D attitudes at all the tracking time nodes will be acquired, and the precision of 3D attitude's calculation results is analyzed. Afterwards, the 3D model of target aircraft is built by 3D CAD software, import the aircraft's 3D model into 3DSmax software, associated it with the moving trajectory, moving parameters and 3D attitudes to establish the simulation model of photoelectric theodolite tracking aircraft. Using it simulate successfully the process of the electrical optical theodolite tracking the aircraft's movement, and obtain the series images of aircraft's tracked by single-theodolite and intersection tracked by two-theodolite. At last, example for the aircraft's cobra maneuver, to verify the solution of 3D computer vision for photoelectric theodolite tracking aircraft which proposed in the dissertation reproduce the aircraft movement and 3D attitudes changes over the tracking time, the results indicate that the above-mentioned method is reasonable, feasible and practical.