1. An infrared camera system, comprising: a sensor adapted to capture a current image of a body of water and a plurality of preceding images of the body of water, wherein the current image and each preceding image all comprise a plurality of digital pixels; and a processor adapted to: determine a plurality of local background models for the plurality of digital pixels in the plurality of preceding images such that each digital pixel corresponds on a one-to-one basis with the corresponding local background model; evaluate each digital pixel in the current image with the corresponding local background model; and detect a petroleum-containing contaminant on the body of water responsive to at least the local background model evaluation for each digital pixel.