Study On Visible Light Scattering Characteristics Of Ground Large Car And Ground Background

The key to the study of the target and ambient light scattering characteristics is how to identify or disguise target information in a complex environmental context.Therefore,the visible spectrum scattering database and model based on the complex structure target in the context of the actual environment have important significance for the related research on the detection and recognition of the target and the environment optical characteristics,and the stealth.Based on the basic theory of BRDF and the five-parameter BRDF model,the paper fits several kinds of typical samples of BRDF measurement data,and analyzes the calculation results and errors.The typical surface BRDF models for desert,soil and vegetation are summarized.Based on MODIS data,the “nuclear drive” model was used to discuss the distribution of BRDF in deserts,grasslands,and vegetations of typical regions at different incident zenith angles,different ground features,different seasons,and different wavebands.The results show that the desert surface is in the same band.The BRDF distribution characteristics in the same incident zenith angle remain basically the same,but in the winter,the BRDF value is slightly larger than other seasons,followed by spring,autumn and summer.In the same season,the same incident zenith angle,BRDF along the desert surface The increase of the wavelength increases;in the same band of the same season,when the observation angle is smaller,the surface BRDF value is closer,and when the observation angle is larger,the BRDF value increases with the increase of the incident zenith angle.Large;Vegetation surface BRDF has “hot spot” phenomenon in different bands in different seasons,BRDF values change significantly with seasons;Grassland BRDF in summer and autumn because of dense grassland BRDF distribution basically consistent with the vegetation change trend,and spring and winter Grassland growth is sparse,and the distribution of BRDF is basically similar to the desert surface.The 3DS MAX software was used to establish a large-scale ground vehicle model.The triangle mesh was meshed and blanked for the model,and the coordinate system was established to obtain the triangle surface coordinates,normal vectors,and surface area of the model.Using the material sample visible spectrum BRDF to fit the calculation results,using the sun as the incident light source,the visible light scattering intensity of the large-scale ground vehicle model was calculated based on the surface element method of RCS target modeling.The effects of different materials,incident angles,and scattering angles on the spectral scattering brightness were analyzed.It can be concluded that when the same material is at a certain incident angle,the spectral scattering brightness of the vehicle at different scattering angles is basically consistent with the wavelength,and the maximum value of the spectral scattering brightness is in the mirror image direction.Using the face element method to calculate the simple rule sphere RCS,and the results compared with the analytical solution of the regular sphere,to verify the correctness of the method.Considering the environment where the target is located,a composite model of ground vehicles and grasslands and deserts was established,and the visible-spectrum scattering brightness of the vehicle and the environment was calculated.It can be concluded that the spectrum scattering intensity is not considered when considering the background of the ground and the background of the environment.It is different,but their spectral scattering brightness is basically consistent with the trend of wavelength change.