Detecting Oil Slicks Under the Heterogeneous Marine Environment Utilizing Multispectral Images

Oil spill incidents endanger the marine environment. A spaceborne multispectral imager can be used to observe the floating oil slicks on a large scale. However, traditional methods are only suitable for small-scale detection situations. It is difficult to distinguish oil slicks from the heterogeneous marine environment in large area images because the spectral information on oil slicks and seawater are analogous and mutative. We suppose that finding out the sensitivities of spectral indices to seawater environment contributes to avoiding identifying seawater as oil slick look-alikes. Based on this assumption, this research conducted experiments to test several proposed oil slick detection indices: fluorescence index (FI), rotation-absorption index (RAI), shortwave infrared (SWIR) reflectance, chlorophyll (CHL) spectral characteristic, and colored dissolved organic matter (CDOM) spectral characteristic. The experimental results indicated that the indices were sensitive to different marine environments and combining the complementary indices could extract oil slicks from the heterogeneous marine environment accurately.