基于半球空间光纤阵列的双向反射分布测量

Measurement of Surface Bidirectional Reflectance Distribution Based on Optical Fiber Array in Hemispheric Space

提出了一种基于半球空间光纤阵列的双向反射分布函数(BRDF)测量方法与系统。将多根光纤组成的阵列均匀分布于一半球面上,使球心处物体表面反射的光在三维空间中的角分布转换为同一平面上的二维图像,经CCD采集及相应的数据处理,可实现对物体表面双向反射分布函数的快速测量。同时,利用光纤将照射激光束传输到物体表面待测点,并通过光纤的弯曲角度可改变光束的入射角。利用该测量系统对不同材质、不同加工工艺的物体表面的激光反射分布进行了初步的测量和分析。结果表明,相比传统的扫描式测量系统,该测量系统在提高测量速度的同时,避免了由于光源功率的起伏和探测器响应度的涨落所引起的测量误差,且结构简单,使用方便。

A novel approach and system for measurement of bidirectional reflectance distribution function （BRDF） based on optical fiber array in hemispheric space are proposed. With a fiber array composed of numerous multimode fibers located uniformly in a hemisphere,the angular distribution of surface optical reflectance in tri-dimensional space is transformed into a two-dimensional planar image. By collecting the image using a CCD camera and going though a corresponding data processing,a fast measurement of BRDF can be realized. Furthermore,the laser beam is transmitted and guided by fibers to irradiate the sample surface in various incidence angles. Primary measurements and analysis of surface reflectance of varied substance along with various machining process are carried out with this system. The results indicate that,comparing with conventional measurement systems,this novel one can avoid the measuring errors generated by the fluctuation of laser power and the sensitivity of the detector,as well as dramatically shorten the acquisition time. In addition,a compact configuration eases the measurement procedure consumedly.