Research On Infrared Radiation Characteristics And Scene Simulation Of Typical Sea Surface

Infrared scene simulation and modeling are widely used in various fields,especially in military field.With the development of marine resources in our country,more and more researchers pay more attention to the research of the typical sea surface infrared simulation.The actual sea surface conditions can be simulated well by the atmospheric data,infrared radiation data and rough surface scattering data.In addition,the rendering of the infrared scene makes the sea surface simulation more realistic,and has very important significance in practical application.The modeling and simulation of rough sea surface in 3-5um infrared band has been focused on this thesis,in addition,the scattering characteristics of rough sea surface in this band has been studied.The main work of this thesis includes the following aspects.1.The sun and sky background infrared radiation and infrared radiation of the sea surface characteristics are analyzed;With the help of MODTRAN software,the calculation process and calculation method of atmospheric transmittance has been given based on the latitude and longitude,time and weather;At the same time,several classical blackbody radiation laws have been described in detail and the relationship between blackbody radiation and temperature has been analyzed.2.Several important eigenvalue expressions in the calculation of wave elements have been described in detail;Several different spectral models have been compared,among them,the power spectrum function of JONSWAP spectrum has better randomness and two dimensional characteristics than the Neumann spectrum and P-M spectrum.Therefore,the JONSWAP spectrum has been chosen as the power spectrum of the sea surface modeling,and the sea surface height spectrum model has been established based on the Monte Carlo method;the simulation of sea wave spectrum under different wind speeds has been listed.3.The infrared radiation characteristics of rough sea surface have been studied,and the solar radiation brightness and sky radiance have been calculated by using MODTRAN software and theoretical formula;this thesis based on the correlation between the temperature and the emissivity of the sea surface,the spontaneous emission brightness of the rough sea surface has been calculated;The BRDF back reflection function has been introduced in this thesis,the principle of surface segmentation to transform the earth coordinate system with different surface elements has been used,and this thesis further studies the scattering characteristics of solar radiation and sky radiance by different surface elements with Cox-Munk scattering model.Through the above calculation,the radiance values of each element of the detector can be obtained.4.The infrared scene simulation of the rough sea surface in the 3-5um band and the sea spectrum model have been completed,including the longitude and latitude,time,weather conditions and so on.Using OpenGL software combined with Visual C++6.0 platform to simulate the results,the effects of different wind speeds and different infrared images on the rough sea surface at different zenith angles have been compared,simulation results show: the sea wave height and sea surface brightness value increased with the increase of wind,and the larger area of bright spots on the sea surface is obtained.With the increase of zenith angle,the larger total brightness of the sea surface and the area of the sea bright spot are obtained.This is consistent with the actual sea conditions.