各向异性发射点源几何外形对目标红外信号的影响

Influences of Geometrical Shapes on Infrared Signatures for Anisotropic Emitting Point Targets

基于材料的各向异性发射特性,以点目标红外探测为应用模型,采用蒙特卡洛法建立从目标到探测器的红外传输模型,分析四种简单几何体表面的各向异性发射特性对目标红外信号的影响。结果表明,点源红外信号对各向异性发射特性的灵敏性与目标几何外形及目标表面发射率的角度分配性有关。当半球发射率保持一定时,点源信号对法向小辐角发射模型灵敏度较高,且增大法向发射率可提高目标总红外辐射强度。另外,相比椭球体、圆柱体和圆锥体,球体红外信号对各向异性发射的灵敏度最低,即发射率的角度分配性对球体目标红外信号影响最小。

The paper applies the anisotropic emission behavior of materials to the point-source infrared （IR） detection research. The target-to-detector IR transmission model is established via the Monte Carlo method, and the effects of the anisotropic emission patterns of the target surface upon the target＇s IR signatures for four simple geometrical objects are investigated. It is concluded that the sensitivity of point-source signals to anisotropic emission behavior is related to the target＇s geometrical shapes and the emission angular patterns of the target surface. As the hemispherical emissivity is kept constant, the signals are highly sensitive to the near-normal emission patterns with narrow radiant angular widths, and increasing the normal emissivity can enhance the total energy intensity. In addition, compared with the ellipsoid, cylinder and cone, the sphere is the least sensitive to anisotropic emission patterns, which signifies that the angular distribution of emission has the minimal impacts upon the sphere.