Research On Image Motion Compensation Method And Control Technology Of Triaxial Image Stabilization Aerial Camera

With the rapid development of aerospace technology,aviation technology has inevitably also been developed rapidly,and the development of aviation cameras is a typical representative of it.While the aviation cameras are widely used,the requirements for the imaging quality of aviation cameras are also getting higher and higher.Aerial cameras generally work at high altitude of thousands of meters,and their working environment is relatively complex,and temperature changes and airframe vibrations can affect the imaging quality of aerial cameras.Where,factors such as the rapid flight of the carrier aircraft and changes in attitude can produce image motion,which can reduce the resolution of the aerial camera and blur the captured image.In this paper,the aerial camera with a three-axis stabilized platform developed by the group was used as a research object,we propose an image motion compensation method based on a three-axis stabilized platform.The method was also verified by simulation and imaging experiments.In the end,for the three-axis stabilized platform control system,under the premise of meeting the aerial camera imaging requirements,a three-axis stabilized platform PID control scheme is designed to realize the aerial camera image motion compensation by controlling the threeaxis stabilized platform.The study’s specifics are as follows:(1)From the theoretical analysis,the concept of homogeneous coordinate transformation method is introduced.and some brief introduction to the matrix transformation of the homogeneous coordinate transformation method.Then the aerial camera imaging coordinate system is established according to the structure sketch of the aerial camera and the homogeneous coordinate transformation matrix between each adjacent coordinate system is calculated,followed by the analysis of the factors affecting the imaging quality of the aerial camera in the operating condition.At the end,the mathematical model of the image motion is calculated using the homogeneous coordinate transformation method.(2)The proposed three-axis stabilized platform-based image motion compensation method is described in detail,and is verified by simulation and experiment.First of all,a brief introduction of the genetic algorithm is given.And then,the mathematical model of image motion was simulated and analyzed using MATLAB.Subsequently,a genetic algorithm is used to compensate the image motion for a certain flight attitude of carrier for aerial cameras,and then a modulation transfer function(MTF)is used to evaluate whether the results of the image motion compensation meet the performance requirements of the optical system.Followed by,the proposed image motion compensation method is optimized,and a genetic algorithm is used to find the optimal flight attitude of carrier for aerial cameras.In the end,the aerial camera imaging experiment was designed to verify the effectiveness of the three-axis stabilized platform-based image motion compensation method proposed in this paper.(3)A system identification method,recursive least squares algorithm,is provided for the structure of the three-axis stabilized platform control system.First of all,we will briefly introduce the content of system identification and the steps of identification.And then,the system identification model structure is established for the three-axis stabilized platform,and the mathematical model for system identification is derived.Subsequently,the objective function of system identification is calculated according to the principle of least squares algorithm,and the mathematical model of recursive least squares identification method is calculated by derivation.In the end,the proposed system identification method is simulated and analyzed using MATLAB.(4)Image motion compensation control of the three-axis stabilized stage using PID control method.First of all,we briefly introduce the PID control system.And then,a simulation model of PID control system was built using Simulink,and P control,PI control,PD control and PID control were simulated respectively,and the simulation results were analyzed according to the step response graph.In the end,the parameters of the PID control system are adjusted,and the simulation analysis of the control system is done using the adjusted parameters.