Oil spills in water present a special challenge for imaging-based detection methods. In the visible-light waveband (VIS for short), ocean water is often murky and appears dark when looking straight down. At high angles, ocean water reflects the sun, horizon, or sky and can appear very bright. Against this highly variable surface brightness, any thin film of liquid floating on the surface can be hard to see with the naked eye or with a color video camera.
Recent investigations by FLIR engineers have determined that there are at least three fundamental reasons why longwave infrared imaging is a powerful tool for spill detection in field conditions.