Infrared imaging systems and methods disclosed herein, in accordance with one or more embodiments, provide for detecting petroleum in an infrared image. The detection involves the evaluation of local background model likelihoods in light of extracted pixel features as well as the evaluation of a global outlier model in light of extracted pixel features. Those pixels having a low likelihood for both their local background model as well as the outlier model are identified as corresponding to oil-contaminated water within the infrared image.