基于双向反射分布函数的发射率测量研究

The emissivity of the material surface is a physical quantity representing the radiation capacity of the material surface and an important thermophysical parameter. It plays a very important role in aerospace, radiation temperature measurement, remote sensing, target recognition, thermodynamic properties of materials, optical constant calculation and other fields. Bidirectional reflection distribution function (BRDF) is a physical quantity that represents the spatial reflection characteristics of the target surface. The BRDF-based emissivity measurement can be used to measure the directional emissivity of the rough surface, which is helpful to study the space radiation characteristics of the rough surface, especially the anisotropic surface. In this project, BRDF measurement technology is applied to the measurement of directional emissivity. The main contents include: 1) investigating of the influence of geometric error and integral error on the measurement accuracy of BRDF comprehensively, and designing reasonable schemes to eliminate the influence of these factors on the measurement accuracy; 2) verify the reliability of the measurement results by comparing them with the authoritative data and the measurement results of the existing emissivity measurement devices; 3) study the change rule of directional emissivity of rough surface with angle, establish mathematical model, and study the space radiation characteristics of material surface by combining BRDF and directional emissivity. The implementation of the project has important theoretical significance and application value for enriching the emissivity of materials and studying the space radiation characteristics of materials.

材料表面的发射率是表征物质表面辐射能力的物理量，是重要的热物性参数，在航空航天、辐射测温、遥感、目标识别、材料的热力学性质、光学常数计算等领域有十分重要的应用。双向反射分布函数（BRDF）是表征目标反射特性的物理量，能够准确描述既定入射方向下材料在半球空间的反射特性。基于BRDF的发射率测量能够很好地实现粗糙表面方向发射率的测量，有助于研究粗糙表面尤其是各向异性表面的空间辐射特性。本项目将BRDF测量技术应用于方向发射率的测量研究，主要内容包括：深入分析几何误差和积分误差对测量精度的影响，设计合理的方案减小这两个因素的影响；通过与权威数据和现有发射率测量装置的测量结果相对比，验证测量结果的可靠性；研究粗糙表面方向发射率随角度的变化规律，建立数学模型，并将BRDF与方向发射率相结合研究材料表面的空间辐射特性。项目的实施对丰富材料的发射率以及研究材料空间辐射特性具有重要的理论意义和应用价值。

发射率是表征物质表面辐射能力的物理量，是重要的热物性参数，在航空航天、辐射测温、遥感、目标识别等领域均有十分重要的应用。本项目将双向反射分布函数（BRDF）测量技术应用于方向发射率的测量中，主要内容包括：通过测试和计算明确几何误差和积分误差的影响，对测量装置进行优化改进消除以上两个误差的影响，提高BRDF的测量精度；对金属和耐高温材料表面的面内-面外（三维）BRDF 进行测量和建模研究，并对模型进行积分获得材料的方向发射率；最后对获得方向发射率数据进行可靠性验证，并开展方向发射率的测量和建模研究。项目的研究工作主要取得了以下研究成果：完成了对BRDF测量装置的优化改进，提高了测量精度；通过测量研究分析了温度、粗糙度等因素对光学散射特性的影响；获得了耐高温材料的三维BRDF测量数据并建立三维BRDF模型，通过计算得到了其方向发射率。在项目的支持下，发表SCI论文2篇，EI论文1篇，授权发明专利2项，培养硕士研究生3名。项目的研究工作对研究材料的空间光学散射和辐射特性具有重要的价值。