Technical Research And Implementation On Image Motion Compensation Of Infrared Array Search System By Fast Scan Imaging

Compared to Linear Detection system,the Infrared Array Searching System features itself with better detection ability and higher scanning efficiency.It can also be one of the research focus in infrared.However,array scanning imaging usually brings the problem of image quality degeneration.The reason is that the object is moving relative to the detection target surface during the detection integration time.This dessertation focuses on the image degeneration problem in array scanning imaging,and also carrys out some research work such as image quality generation mechanism analysis,image motion compensation schemes comparison,and studys on FSM(faststeering mirror)servo control strategy of high frequency and large tilt angle.The research includes the following parts:1.Analysis on infrared array scanning detection mechanism.Based on dynamic optics theory,we deduced the infrared array scanning image motion equation and effect of moving base on elevation stabilized equation.Several issues of infrared array scanning imaging under the two-dimensional searching are analyzed,including image motion,field rotation,compensation rate fluctuation,and so on.We also worked out some parameters of the compensation system,such as bandwidth,position accuracy,and velocity accuracy,which offers theories and design supports to the detailed scheme,making a deep study on image motion compensation scheme in the infrared array searching system and coming up with an image motion compensation method using FSM.2.An image motion compensation control strategy of IRST(infrared search and track)under real-time LOS(line of sight)tracking is proposed.It matches the orientation searching turntable and the compensation mirror.The disturbance rejection and control bandwidth of FSM servo system have been significantly improved while the image motion compensation of high quality under orientation searching turntable variable motion and certain pitch angle.High-precision velocity measurement algorithm is adopted to achieve the real-time measuring of orientation searching turntable velocity.By using SIMULINK,we built up the galvanometer-controlled model and made simulation analyses of the bandwidth,step response and antidisturbance ability of current loop and speed loop as well as position loop in the servo system.The simulation and experimental result proved that this method can effectively improve the bandwidth of the galvanometer-controlled system and then achieve highquality imaging under fast array scanning.3.A continuous infrared array scanning detection system with function of image motion compensation is designed and worked successfully.With image space scanning image motion compensation skill,the continuous infrared array scanning imaging is achieved.We also worked on the design of compensation servo system,including model selection of key components,and software and hardware realization of the servo system.An experimental prototype of infrared array searching system is set up,by which the image motion compensation of fast array scanning imaging is achieved.4.The verification scheme for image motion effect is designed,and the test platform of image motion compensation in the infrared array searching system is built.The image motion compensation effect is evaluated by testing the MTF of infrared array searching system with laboratory target.We also conducted an experiment of systematical outfield panoramic searching imaging and completed qualitative and quantitative analyses image motion compensation under fast array scanning imaging,by which the MTF(modulation transfer function)of infrared array searching system measured by slanted-edge method and the quantitative indicator for the imaging quality of infrared array searching system.The MRTD(minimum resolvable temperature difference)and MTF of none-compensation image,after-compensation image and none-image-motion image are respectively measured,which prove that the galvanometer-based de-scanning compensation scheme can effectively meet the requirement of image motion compensation for fast array scanning imaging,and the imaging quality is similar to that of the staring system.Basically this paper has demonstrated two things.One is that the continuous scanning staring compensation can dramatically realize the image motion compensation for fast array scanning imaging,significantly shortening the settling time between frames,giving full play to the advantages of high frame-frequency of array detector and improving the frame-frequency and scanning efficiency of the system.The other is that the image motion compensation control strategy of IRST under real-time LOS tracking can effectively promote galvanometer controlling,quickly matching galvanometer with the orientation searching turntable under variable speed,And image motion residual is less than one third pixel after compensation,to get high-quality image motion compensation of infrared array searching system.