Research On Monocular Vision Pose Measurement Based On Orthogonal Iteration Algorithm

Wind tunnel test is an important method to study the external stores separation problem,and to determine the important means of the buried weapons,more for providing the experimental data and method.We can verify the separation characteristic and analysis the design of aircraft control system by wind tunnel test.Thus,it is important to accurately measure the aircrafts separation parameters(including position,attitude,etc.).The traditional capture trajectory system(CTS)and multiple exposure photogrammetry methods are still difficult to measure the separation parameters of the casting,and it can not meet the current large field of view,high precision and high efficiency wind tunnel test.The monocular visual pose measurement is widely used in the experiment of wind tunnel test because of its large field of view,accurate measurement speed and easy installation of wind tunnel environment.Based on the theory of monocular visual pose measurement,this paper has carried out the research on the high-accuracy measurement of the pose parameters by monocular vision.We discussed the key technology of monocular visual pose measurement and the system was designed and developed.The main research contents included the following:(1)The camera calibration and distortion correction were studied.We calibrated the camera through Zhang Zheng You calibration method and used distortion correction model to correct camera.The total mean value of the experimental results was 0.18 pixel.The analysis of the error shows that the method had a high accuracy and stability,and can meet the requirements of high-accuracy measurement(2)We analyzed and compared the design of circular coded marks,the most suitable marks tracking and recognition algorithm,and the center location of the circular coded marks in monocular visual measurement.In this paper,we used the eight-domain boundary tracking algorithm to solve the problem of low accuracy and poor stability,the center location of the circular coded marks was based on the gray center of gravity method.The experimental results showed that the detection rate and accuracy of this method were 100%,which can adapt to the complex wind tunnel experiment environment.The center localization algorithm had high positioning accuracy and strong anti-noise ability.(3)We summarized the common pose estimation method in monocular vision pose measurement,and deduced the orthogonal iterative algorithm’s mathematical model of pose estimation.At the same time,considering the measurement accuracy and real-time requirement of pose measurement,an improved orthogonal iterative algorithm was proposed.The traditional orthogonal iterative algorithm was accelerated and the pose fuzzy problem in pose estimation was solved.The experimental results showed that the method proposed in this paper had better accuracy and higher efficiency.(4)We designed and developed a monocular visual pose measurement system.Respectively,we designed the monolithic pose measurement system of the overall program design and system function modules.The experimental results showed that the translational precision is 0.2 mm and the rotation precision is 0.2°.At the same time,we also analyzed the influence of vibration on pose measurement in wind tunnel experiment environment,and proposed the vibration error compensation strategy of pose measurement.