Research Of Airborne High Resolution Thermal Infrared Imaging System With Wide Field Of View

The thermal infrared remote sensing and imaging system uses the radiation intensity of long wave infrared as the sensitive source.Through the passive thermal radiation detection by thermal infrared detectors,the infrared thermal imaging of the ground target is realized.Compared with visible imaging system,the thermal infrared remote sensing has the technical characteristics of all day work and long distance temperature measurement,and it has wide application prospect in resource exploration,environmental monitoring,military reconnaissance and personnel search and rescue.However,the domestic thermal infrared remote sensing and imaging system is mostly based on the unit or line detector,which leads to the limitation of detector size and can not meet the requirements of imaging field,spatial resolution and temperature sensitivity.Coupled with the limitation of existing imaging technologies,the volume and weight also can not comform to the light and miniaturization development trend of remote sensing system.In this paper,the wide field imaging technology is studied in detail,and the advantages of the two-way array scanning technique in improving the imaging field and spatial resolution are analyzed.According to the working principle of thermal infrared camera,the imaging indicators,application prospects and other aspects to the system adaptability are compared between the cooled and uncooled infrared camera.In order to ensure the camera absolute stability to the ground at the imaging moment,the image motion compensation technology and the aircraft attitude disturbance isolation technology are studied.Considering the long response time of uncooled infrared camera,the paper creatively proposed swing-stop gaze imaging compound roll posture disturbance isolation technology at wingspan direction,and the motion forward compensation compound pitch posture disturbance isolation technology at flight direction.The imaging technology not only realizes the wide field of view and the high spatial resolution Image acquisition of the uncooled infrared camera,but also ensuring the stability of the imaging field of view and reducing the system size and weight.The paper analyzes the performance of system motion actuator,and establishes the motion control model according to the voice coil motor and permanent magnet synchronous motor mechanical structure.The mathematical model of the motor is built by Matlab,and the effect curves controled by constant acceleration,S-type acceleration and sine acceleration is obtained by Simulink simulation tool.With above studies,the motion control strategy of system motor is selected.Combining with system control accuracy and design,the PID three-loop plus feedforward control algorithms are researched.The paper designs the hardware structure and software control program of the system key parts and develops the scanning motion test device to prove the motion scheme and algorithm can guarantee the control error within one pixel at the imaging moment.Aiming at the continuous response mechanism of thermal detection,a video stream extraction method is proposed,which realizes the single frame triggering function.Using Labview to complete the design of the host computer interface,and the real-time communication between host computer and imaging system is achieved.The six directions motion platform is used to simulate the flight test in the room,which verifies the system function to obtain wide field of view and high resolution images.Using Y5 aircraft as the airborne platform and the outside field flight test was carried out in the Jiaxing,Zhejiang,which obtains the thermal infrared remote sensing images with the wide and stable field of view.According to the test data,the studies of thermal infrared lens distortion correction are accomplished.With the two types of target production materials of black aluminum oxide and electroless nickel-aluminum are obtained by theoretical analysis and experimental imaging,the reference for target materials selection of thermal infrared lens distortion correction is provided.Finally,the geometric distortion correction model based on the system imaging method and the temperature inversion correction method are studied to improve the accuracy of image localization and splicing,and the error of system temperature inversion is reduced.