Study On The Influence Of Background Radiation On The Performance Of Infrared Detection System

This paper focuses on the influence of background radiation on the performance of infrared detection system.Background radiation affects the core detection ability of infrared detection system by two aspects: the increase of the integral time and the noise of the system.The purpose of the study is analyzed under the conditions of different scenarios and backgroundradiation,each component of background radiation effects on the performance of infrared detection system,in order to optimize the design of infrared detection system,make effective use of system provides recommendations.This paper takes the typical long wave coaxial four anti infrared detection system as an example,studies the influence of the background radiation on the infrared detector's saturation integral time,specific detection rate and the infrared detecting system's noise equivalent flux density NEFD and the detection distance.Main contents are summarized as follows:(1)The composition and characteristics of background radiation are analyzed,and the numerical simulation of background radiation is carried out.Analysis of the atmospheric radiation,optical system spontaneous radiation,detector spontaneous radiation characteristics,focusing on the factors affecting the size of the atmospheric radiation,establish the atmospheric radiation,optical system spontaneous radiation and detector spontaneous radiation numerical model.The relationship between the atmospheric radiation,the spontaneous radiation of the optical system and the spontaneous radiation of the detector under the usually condition is compared.(2)Bythe calculation of atmospheric radiation,optical system spontaneous radiation,detector spontaneous radiation,we theoretically analysis the influence of background radiation on the infrared detector's integral time,specific detectivity,infrared detection system's noise equivalent flux density and the detection range.With the decrease of atmospheric radiation,infrared detectors available integral time increase,ratio detection rate decreases,so as to reduce the infrared detection system noise equivalent flux density,increase the detection distance,under different atmospheric radiation,inhibition of spontaneous emission of an optical system,detector spontaneous radiation effect of improving the performance of infrared detection system,is different.(3)Set up the experimental platform for the research of background radiation.Emphasis is put on the design and analysis of background radiation simulation plate and its switching equipment.The thermodynamic analysis and radiation propagation was carried out on the background radiation simulation plate and its switching equipment,and test the results.The test results show that: background radiation simulation plate can simulate atmospheric radiation,good uniformity of surface treatment,the emission rate of the background radiation simulation plate has little difference with commercial blackbody,the temperature stability of the background radiation simulation plate and the uniformity of the temperature in the plate all meet the experimental requirements,to solve the problem of atmospheric radiation simulation and low-temperature radiation source in the experimental study(4)The influence of background radiation on the performance of the infrared detection system is analyzed,and the experimental results are analyzed and the optimization suggestions are put forward.The effects of different atmospheric radiation on the saturation integral time and specific detection rate of infrared detectors are studied.The noise equivalent flux density NEFD of the infrared detection system under different atmospheric radiation is calculated.At the same time,study the influence of the optical system spontaneous radiation,detector spontaneous radiation on NEFD of infrared detection system,the experimental results of the spontaneous emission level of the optical system and the infrared detectorare in agreement with the numerical results,which proves the correctness of the numerical simulation.The effect of improving the performance of infrared detection system by reducing the infrared detector spontaneous emission and the optical system spontaneous emission,which is different in the face of different atmospheric radiation.Finally,suggestions are made on the optimization of infrared detection system at different observation platforms.