Study On Simulation Technology For Propagation In The Atmosphere Of Infrared Radiation

With the continuous improvement of computer simulation technology and hardware equipment performance, the simulation technology of infrared images could generate infrared images of target and background under different atmospheric condition in different seasons at various times. Therefore, it is prospering in recent years and used in many areas widely. When infrared radiation (IR) transmits in the atmosphere, it would be affected by the atmospheric transmission effect which has a great influence on quality of infrared images. So constructing the model of atmospheric transmission effect of IR is very necessary. Based on study about the reason and principle of atmospheric transmission attenuation effect and atmospheric distortion, systemic conclusion and summary about research status, this paper studies the simulation model of atmospheric transmission attenuation effect and atmospheric distortion of IR, the simulation model of atmospheric transmission effect of infrared radiation based on Monte Carlo method(MCM),which lay the foundations for atmospheric transmission effect simulation of infrared images.Firstly, applying the method combined theories and empirical formula, the model of atmospheric transmission attenuation effect of IR is builded. After that, the comparative experiments of calculating atmospheric transmittance with MODTRAN (MODerate resolution atmospheric TRANsmission) are carried out to validate the reliability and accuracy of simulation model which provides operability and computation efficiency.Secondly, based on the theories of atmospheric transmission, using typical MTF (Modulation Transfer Function) models of turbulent and aerosol, the model of atmospheric transmission distortion effect of IR based on MTF is established with several meteorological data. After that, several prediction models of pivotal parameters of MTF of atmospheric turbulence and aerosols are analyzed and compared in order to choose the appropriate model which is accordance with the actual case.Then attenuation of IR absorption and scattering caused by atmospheric aerosol and molecules is studies. By using Monte Carlo Method (MCM) to simulate the process of the transmission of photons in the atmosphere, PSF (point spread function) is counted. And a simulation model of atmospheric transmission effect is established based on MCM. It is applicable to simulating the effect of rain and fog. Considering the limitation of long execution time and bad convergence of MCM, a parallel optimized method based OpenMP (Open Multiple Processing) on multi-core CPU platforms is performed to improve computation efficiency greatly. Finally, based on the studies about model of atmospheric transmission attenuation effect and atmospheric distortion of IR. the simulation system of atmospheric transmission effect of IR is designed and established. Then simulation experiments of atmospheric transmission effect of IR ground scene are performed under brighter and rain weather condition based simulation flowchart. After analysis and comparison of several statistical index of image evaluation between original and simulating infrared images, it proves that simulation models and algorithmic systems in this paper could provide superior reliability and credibility.