We present a bidirectional reflection distribution function （BRDF） model for thermal coating surfaces based on a three-component reflection assumption, in which the specular reflection is given according to the micr...We present a bidirectional reflection distribution function （BRDF） model for thermal coating surfaces based on a three-component reflection assumption, in which the specular reflection is given according to the microfacet theory and Snell＇s law, the multiple reflection is considered Nth cosine distributed, and the volume scattering is uniformly distributed in reflection angles according to the experimental results. This model describes the reflection characteristics of thermal coating surfaces more completely and reasonably. Simulation and measurement results of two thermal coating samples SR107 and S781 are given to validate that this three-component model significantly improves the modeling accuracy for thermal coating surfaces compared with the existing BRDF models.展开更多
A precise modeling method of visible characteristics of the space-based target was presented based on bidirectional reflection distribution function (BRDF). The background characteristics of the space-based target wer...A precise modeling method of visible characteristics of the space-based target was presented based on bidirectional reflection distribution function (BRDF). The background characteristics of the space-based target were represented to build models of direct solar radiation and reflected radiation of the Earth based on blackbody radiation theory. The geometry characteristics of the target were analyzed to establish a surface equation of each surface based on its body coordinate system. The material characteristics of the target surface were described by introducing a BRDF model which considers the character of surface Gauss statistics and self-shadow and is obtained by measurement and modeling in advance. The relative positions of the space-based target, the background radiation sources and the observation platform were determined based on coordinate con- version to judge contributing surface of the target to observation system. Then a mathematical model on visible characteristics of the space target for the given optical system was built by summing reflection components of all the surfaces. Simulation of visible characteristics of the space-based target in orbit was achieved according to its given geometrical dimensions, physical parameters and orbital parameters. The results show that the method is effective for analysis on visible characteristics of the space-based target when single reflection is considered and its surface is regularly described in a surface equation, which provides a way to real-time calculation of visible characteristics of the space-based target.展开更多
利用二向反射分布函数(binomial reflection distribution function,BRDF)理论,结合目标表面的镜面反射和漫反射分量,建立完善的偏振二向反射分布函数(polarization binomial reflection distribution function,pBRDF)模型,并通过不同...利用二向反射分布函数(binomial reflection distribution function,BRDF)理论,结合目标表面的镜面反射和漫反射分量,建立完善的偏振二向反射分布函数(polarization binomial reflection distribution function,pBRDF)模型,并通过不同入射角、散射角下pBRDF的仿真模拟数据与实验数据的比较分析,初步断定该模型可准确描述目标的偏振特性。基于该偏振模型,进一步对pBRDF与目标材料的粗糙度以及复折射率的变化进行仿真。仿真结果表明:目标pBRDF的峰值随着粗糙度的增大逐渐减小,随复折射率的增大逐渐增大。展开更多
文摘We present a bidirectional reflection distribution function （BRDF） model for thermal coating surfaces based on a three-component reflection assumption, in which the specular reflection is given according to the microfacet theory and Snell＇s law, the multiple reflection is considered Nth cosine distributed, and the volume scattering is uniformly distributed in reflection angles according to the experimental results. This model describes the reflection characteristics of thermal coating surfaces more completely and reasonably. Simulation and measurement results of two thermal coating samples SR107 and S781 are given to validate that this three-component model significantly improves the modeling accuracy for thermal coating surfaces compared with the existing BRDF models.
基金supported by the National High-Tech Research and Development Program of China ("863" Program) (Grant No. 2006AA704214)
文摘A precise modeling method of visible characteristics of the space-based target was presented based on bidirectional reflection distribution function (BRDF). The background characteristics of the space-based target were represented to build models of direct solar radiation and reflected radiation of the Earth based on blackbody radiation theory. The geometry characteristics of the target were analyzed to establish a surface equation of each surface based on its body coordinate system. The material characteristics of the target surface were described by introducing a BRDF model which considers the character of surface Gauss statistics and self-shadow and is obtained by measurement and modeling in advance. The relative positions of the space-based target, the background radiation sources and the observation platform were determined based on coordinate con- version to judge contributing surface of the target to observation system. Then a mathematical model on visible characteristics of the space target for the given optical system was built by summing reflection components of all the surfaces. Simulation of visible characteristics of the space-based target in orbit was achieved according to its given geometrical dimensions, physical parameters and orbital parameters. The results show that the method is effective for analysis on visible characteristics of the space-based target when single reflection is considered and its surface is regularly described in a surface equation, which provides a way to real-time calculation of visible characteristics of the space-based target.
文摘利用二向反射分布函数(binomial reflection distribution function,BRDF)理论,结合目标表面的镜面反射和漫反射分量,建立完善的偏振二向反射分布函数(polarization binomial reflection distribution function,pBRDF)模型,并通过不同入射角、散射角下pBRDF的仿真模拟数据与实验数据的比较分析,初步断定该模型可准确描述目标的偏振特性。基于该偏振模型,进一步对pBRDF与目标材料的粗糙度以及复折射率的变化进行仿真。仿真结果表明:目标pBRDF的峰值随着粗糙度的增大逐渐减小,随复折射率的增大逐渐增大。
