利用自行研制的双向反射分布函数(BRDF)测量装置测量了可见光波段紫铜表面的面内光谱BRDF。分析了波长、入射天顶角、表面粗糙度等因素对测量结果的影响。结果表明: (1)BRDF随波长的变化主要受样品表面颜色的影响, 与入射和反射角度无关; (2)入射天顶角对测量结果有明显的影响, 主要归结于角度因子和反射强度随入射天顶角的变化; (3)粗糙度对测量结果也有明显的影响, 随着粗糙度的增加, 样品在镜面反射方向的反射减弱, 在其它方向的反射增强。另外, 分别采用不同的分布函数对测量结果进行了拟合, 结果表明, 采用Lorentz分布能够得到更好的拟合结果。

In this paper, the in-plane spectral bidirectional reflectance distribution function(BRDF) of red copper surfaces in the waveband of visible light was measured using a self-developed measuring device. The influences of wavelength, incident zenith angle and surface roughness on the measurement results were analyzed in detail. The results show that the BRDF curve versus wavelength is mainly affected by the color of the sample surface and is not affected by the incident and reflected angle; the incident zenith angle has obvious influence on the measurement results, which can be attributed to angle factor and the change of reflectance intensity varying with incident zenith; and roughness has a significant impact on the measurement results. With an increase of roughness, the reflection near the mirror′s direction is weakened, while the reflection in the other directions is strengthened. In addition, Gauss and Lorentz distribution functions are used to fit the measurement data and the fitting results are incoordance with Lorentz distribution.