Research On High Sensitivity Long Wavelength Infrared Information Acquisition Technology

The research of high sensitivity long wavelength infrared detection technology is of great significance for the development of new space-based infrared detection systems and effective detection of moving targets in space.The radiation characteristics of moving targets in space are studied around the infrared detection method.The model and index of infrared detection system are pre-designed and analyzed.The technical way to improve the sensitivity of LWIR detection system is studied from the perspective of information acquiring.The infrared detection chain of the space moving target is introduced.The detection model including the target radiation characteristics,optical system,infrared detector and information acquisition system is established.An observation model similar to the astronomical infrared observation model is proposed.The key factors that affect the detection sensitivity of the infrared system are analyzed.On the basis of infrared detection path model,a complete chain simulation system of infrared moving target covering target scene,camera load and information processing is developed.The effectiveness of the system for space target detection simulation is verified.In order to reduce information acquisition noise and improve detection sensitivity,an adaptive conditioning information acquisition technology is proposed.The theoretical basis and adaptive updating algorithm of the technology are introduced,and the theoretical analysis of reducing the information acquisition noise by the technology is carried out.The information acquisition system has been developed to realize the adaptive conditioning information acquisition technology.A series of tests,such as information acquisition noise test,were carried out to verify the effectiveness of the technology.The experimental results show that the information acquisition noise of the system is only 0.065mV,which is 40%of the system noise of the information acquisition system of fixed conditioning parameters.Applying the adaptive conditioning technology,the noise of the infrared verification system can be reduced by about 5%.The paper analyzes the source of spatial heterogeneity and the time domain instability of the infrared system.Two non-uniformity correction methods based on the scene are proposed,that is,the non-uniformity correction method based on the BRISK feature and the non-uniform correction method based on the two-dimensional scan.The algorithm principles and steps,experimental results and analysis of the two methods are introduced.The method of non-uniformity correction based on BRISK features is applicable to scenes with complex motion such as translation,scaling and rotation.The algorithm is fast and effective for fixed pattern noise correction.The non-uniform correction method based on two-dimensional scanning is suitable for space-based infrared loads with scanning and pointing mechanism.The residual non-uniformity of the corrected image is better than 1.85%.A high sensitivity long wave infrared verification system is developed with a type-Ⅱ superlattice LWIR detector,the detection spectrum of which is 8¹2μm and the format of which is 320×256.The overall design of the system and the design scheme of the high-sensitivity information acquisition system are introduced.A number of system tests and verification were carried out.The performance of the information acquisition system,the performance of the detection system for the room temperature and low temperature blackbody were tested,and the laboratory and field imaging experiments were carried out.The experimental results show that the NETD of the verification system is about 19.6mK,the detection rate of the blackbody is 7.72×10¹⁰ cm?（?）.The sensitivity of the system is high.The field imaging effect is good,the image details are clear,and the contrast of the images is high.The research results can provide technical support for the high sensitivity space-based LWIR system,and have the guiding significance for the space moving target detection by using the space-based infrared detection means,and provides experimental data analysis and technical verification for the feasibility of type Ⅱ superlattice LWIR focal plane detector applying to high sensitivity infrared detection system.