Dynamic Simulation Of Airborne Infrared Imaging System In Complex Meteorological Environment

Image is the most commonly used information carrier in airborne infrared imaging system.High quality image can better convey the background information of ground,sea and other targets.However,the complex meteorological environment causes great interference in the process of target imaging,which leads to the phenomena of blur,noise,phase distortion,content loss and so on.Atmospheric turbulence and aerosols have the most obvious influence on infrared radiation in the meteorological environment,among which atmospheric turbulence is expressed by atmospheric refractive index structure constant and aerosols is expressed by visibility.Through the analysis of different refractive index structure constants and aerosols,it can provide practical guidance for improving image quality and target acquisition,tracking and recognition of airborne infrared imaging system in two meteorological environments,and further improve the theoretical analysis.Therefore,the main contents of this paper are as follows:Firstly,the model is built through the imaging process of the infrared imaging system.Based on the model and the atmospheric transmission theory,the atmospheric turbulence intensity is built based on the random fluctuation model of the atmospheric refractive index,and the height of the carrier is considered as the variable.The dynamic model of atmospheric turbulence under the airborne infrared imaging system is built,and expressed by the dynamic modulation transfer function.Based on the atmospheric scattering model of Mie scattering theory,using the transmittance of 3～5μm Medium Wave Infrared in the atmospheric transmission as the mixing factor,using visibility to represent the aerosol concentration,using the depth of scene to realize the real-time change of the distance between the airborne infrared imaging system and the observation target,so as to establish the aerosol dynamic simulation model.Then,the three-dimensional dynamic scene is constructed by the physical model of infrared radiation,which is similar to the real infrared scene.Atmospheric turbulence and aerosol effect are added into the scene.For atmospheric turbulence,the main way to achieve it is to generate atmospheric refractive index structure constant at different altitudes.The turbulence modulation transfer function is constructed by atmospheric refractive index structure constant.The Gaussian function is filtered by atmospheric refractive index power spectral density as the wave function of turbulence modulation transfer function.The two functions are added together and change in the interval time to produce the dynamic fuzzy effect of turbulence.For aerosols,the distance between the viewport and the target background is obtained,which exists in the vertex program,so as to realize the dynamic process of aerosols with scene depth and visibility as the variable.Finally,the main purpose of simulating the complex meteorological environment in the airborne infrared imaging system is to analyze the gray distribution,contrast and edge detection objectively and quantitatively,combined with the physical imaging process of the airborne infrared imaging system,and get the comprehensive conclusion that the meteorological environment will reduce the gray value range of the airborne infrared imaging system,the contrast between the target and the background,and the edge details.At the same time,the operating distance of airborne infrared imaging system is evaluated.The results show that the operating distance of airborne infrared imaging system is smaller under atmospheric turbulence and aerosol environment.In the complex atmospheric environment such as atmospheric turbulence and aerosols,the airborne infrared imaging system simulation platform built in this paper can assess the performance of the airborne infrared imaging system,predict the imaging quality and target acquisition,and provide feedback for the follow-up photoelectric system development.