由于现有的双向反射分布函数(BRDF)测量装置多为3轴系统, 不能完全实现样品表面以上2π空间的全角度BRDF测量, 本文研制了新型BRDF测量装置。该新型装置采用高精密六轴串联机械手作为待测目标的定位机构, 使待测目标在测点进行三维转动;采用竖转台作为探测器探头的定位机构, 使探头指向绕测点进行一维转动, 从而形成4维转动以构建BRDF测量所需的4角几何关系。研制的装置可测量的入射和反射光束角度为: 方位角0~360°、天顶角0~70°;光谱可扫描区350~2 500 nm。BRDF测量过程由测控软件控制, 可高精度、无遮挡、全自动、快速地构建BRDF测量几何关系, 一次待测目标和探测器定位以及光谱扫描、传输、显示、存储平均用时约8 s, 测量不确定度优于2 5%(k=2)。

As existing Bidirectional Reflectance Distribution Function (BRDF) measuring device is three-axis equipment, and it can not implement the whole angle BRDF measurement in a 2π space on the sample surface. Therefore, a new device was built for BRDF measurement in this paper. A six-axis robot was used as object positioning mechanism to implement three-dimensional rotating for changing the normal direction of the object at the measuring point, and a turntable was used as the detection positioning mechanism to implement one-dimensional rotating for changing the orientation of detector around the measuring point, so that four-dimensional rotation was constructed to form the four-angle geometry of BRDF measurement. The measuring geometry of incident and reflected beams of the device shows its azimuthal angle to be 0—360°, zenith angle to be 0—70°, and the spectral range is 350—2 500 nm.The process of BRDF measurement is controlled by software, and the BRDF measuring geometry is constructed with high-precision, non-blocking, fully automation and speediness. With an average measurement of about 8 s, the device completes the geometry of construction and spectral scanning, transmission, display and the storage. The uncertainty budget of the device is less than 2.5%(k=2).