Multi-spectral bidirectional reflectance characteristics of crude oils

•Multi-Spectral polarized BRDF characteristics of three crudes were investigated experimentally.•The effect of oil components on BRDF is discussed.•The optimal observation conditions for oil detection are given based on the analysis of contrast. Bidirectional reflectance distribution function (BRDF) has important and extensive applications in remote sensing. The polarized light field is certainly promising for it has the capacity of transmitting more information. In this study, total and polarized BRDF in visible and near-infrared bands of three crudes and pure water were measured through a self-designed scatterometer. The spectral and angle profile properties of BRDF were analyzed. The results indicate that it is achievable to detect crude from the background of water and identify oil types via characteristics of BRDF. The BRDF of the four liquids is in connection with its components. The value of BRDF of the Daqing crudes is significantly higher than that of water for the energy consumption efficiency of water molecules is higher than oil. In contrast, the high content of asphalt of Gudao crude result in it has a lower BRDF value and exhibits a slighter diffuse reflection characteristic. Furthermore, a relative contrast was adopted to assess the detectability of oil, and the conditions when relative contrast to maximum was given. The polarized parameters exhibit its advantage in oil detection with greater relative contrast and reflected intensity at optimal observation conditions.