Study On Spectral Scattering Properties Of Target With Irrgular Fold Surface

There are academic significance and wide application value for research on thespectral scattering properties of the target with irregular fold surface in the areas oftarget detection, recognition, remote sensing, diagnosis of surface features, et al. Bycombining the three-dimensional reconstruction theory with the investigation on thelight scattering properties of the target surface, the3D models of the targets withirregular fold surface are reconstructed and the spectral scattering properties of thetarget in a complex background are studied in this thesis, the distribution of the spectralscattering radiance of the targets like a car covered with a garment and a satellite withfold surface is calculated, and influence factors are analyzed.The main work and achievements are as follows:1. Based on the roughness parameters of the target sample and the metrical data ofthe specular reflection spectrum in waveband0.5μm~1.5μm, the complex refractiveindex and the dielectric constant of the sample in waveband0.5μm~1.5μm are deducedwith the Kramers-Kronig(K-K) method, the dielectric constant in the near infrared bandis extrapolated; combining with Bidirectional Reflectance Distribution Function (BRDF)model of rough surface, BRDF of the sample in band0.5μm~2.5μm is obtained.2. Based on the five-parameter semi-empirical BRDF model, a six-parameterBRDF model is proposed. The model has advantages of simple form, good fitting effect,and obedience to the energy conservation and the reciprocity. Compared with thefive-parameter semi-empirical BRDF model, the new model can fit better for thematerial with weak scattering properties.3. The spatial distribution formula of the spectral scattering radiance of anon-lambertian target in complex background is derived. The solar spectral irradianceand the sea&the sky background’s spectral radiance are calculated by ModtranSoftware, combing with the spectral BRDF of the target sample, the spatial distributionof the spectral scattering radiance of the targets with lambertian and non-lambertiansurface, horizontal and vertical attitudes, is calculated numerically in waveband0.4~0.7μm,3~5μm and8~12μm, influence factors are analyzed.4. According to the theory of3D reconstruction,3D model of the target shape withfold surface is reconstructed. Based on the six-angle images, by feature extraction andmatching, reconstruction of projective structure, camera self-calibration and Euclideanreconstruction,3D points cloud of the fold surface is reconstructed. By the matching points as nodes, the target surface and the normal vector of surface element are obtainedwith the method of Delaunay triangulation and the principle of "visibility". Combingwith the spectral BRDF of the target sample and spectral radiance of background, thedistribution of the spectral scattering radiance of the reconstructed car and satellite incomplex background are calculated numerically, and the impact of target shape onspectral scattering properties is analyzed.5. The spectral scattering properties of fold surface of satellite coating material isanalyzed. Combining with the satellite orbit theory, by calculation of geometric satellitemodel, orbit parameters, coordinate transformation and the sun-the Earth atmospherebackground’s spectral radiance, the distribution of the spectral scattering radiance of thesatellite with fold surface in the foundation detection and space-based detection isemulated numerically, the spectral scattering properties is compared with the satellitewith unfold surface.6. The impact of the light reflected by cloud on the spectral scattering properties ofspace satellite is studied theoretically. According to the height of the cloud layer, it is cutinto meshes in terms of its longitude and latitude, the distribution of the cloud layer’sspectral radiance and spectral scattering is analzsed, the spectral scattering properties ofsatellite from the cloud layer’s spectral scattering are studied. The result shows thecloud layer’s reflectance in the visible waveband has important impact on the spectralscattering properties of the target.