Abstract:Bidirectional Reflection Distribution Function (BRDF) describes the scattering and reflection characteristics of material surfaces. Considering the complex structure, difficult disassembly, and difficult optical path debugging of current BRDF measurement systems, a portable BRDF measurement system has been designed. The measurement system mainly consists of three parts: the light source system, the detection system, and the angle device. The mechanical structure of the angle device and the detection part has been optimized. In order to verify the comprehensive performance of the designed measurement system, experimental measurements were conducted on the surface of typical coating materials using the measurement system, and the influence of incident angle on the surface reflection characteristics of objects was analyzed. The experimental results show that the larger the surface roughness of typical coating materials such as quartz, alumina, and zirconia, the smaller the proportion of mirror reflection. Between 0° and 60° incidence angles, the surface BRDF value also increases with the increase of incidence angle. The measurement data predicted by the improved Torrence Sparrow model was used for fitting analysis with the experimental data. The fitting results showed that the measured experimental data had a good fit with the theoretical model prediction data, with a minimum fit greater than 96%.