航天消光黑漆双向反射分布函数的测量与应用

为了了解经过消光黑漆(Z306)喷涂处理后航天相机遮光罩表面对杂散光的散射特性,对喷涂了Z306的铝板样品进行了双向反射分布函数(BRDF)测量和建模分析。通过测量获得了黑漆样片在0.65μm波段的BRDF值。结合Z306黑漆测量数据的散射特征,选择了适合粗糙黑漆表面的Microfacet-based模型,并对模型进行了修正。使用修正的Microfacet-based模型对测量数据处理并建模,得到了样片整个半球空间的BRDF数据,弥补了测量数据量少和测量误差带来的缺陷。将黑漆的BRDF数据代入软件,分析并进行了光学系统杂散光测试验证。结果表明:采用修正的Microfacet-based模型处理黑漆的BRDF后,分析光学系统杂散光(点扩散函数,PST)得到的结果与实际测量的杂散光(PST)的一致性很高,实测值与分析值比值的对数精度优于0.5。得到的结果证明了BRDF建模的必要性和数据处理的准确性,为光学系统的杂散光抑制提供了重要的保障。

BRDF measurement of matte coating and its application

To explore the scattering characteristics of the stray light on hood surface of a camera ,the Bidirectional Reflectance Distribution Function (BRDF) of the matte coating (Z306) on a aluminium plate specimen was measured and modeled to suppress the stray light . The BRDF value of the specimen coated with matte coating Z 306 at 0 .65 μm was obtained .On the basis of the scattering characteristics of the specimen coated with matte coating Z 306 ,the microfacet-based model suitable for roughness matte coating was selected and corrected .The corrected microfacet-based model was used to model and process the measurement data and to obtain the BRDF data of the specimen in the whole hemisphere space to make up the defects of the less data and measurement errors .The BRDF data of the matte coating was induced to the software to analyze the stray light of an optical system and to compare the performance with the results of the stray light measurement .It shows that after the measurement data are processed by the correction microfacet-based model ,the analysis results of the stray light have high consistency with the measurement results of the stray light , and the logarithm value of the ratio of tested value and analyzed value is less than 0 .5 . The results demonstrate that the BRDF model is necessary and the data processing is accurate ,which provides an important method for stray light suppression in optical systems .