With this kind of system it is possible to get a picture of the thermal environment that we cannot experience with our normal human sensors. The ability to record variations in infrared radiation has tremendous application in extending our observation of many types of phenomena in which minor temperature variations may be extremely significant in understanding our environment. For example, potential safety or environmental problems can be spotted by monitoring the water temperature of cooling ponds and rivers near power plants. This thermal IR image depicts warmer areas in brighter tones. Cooler areas are darker.
Water is the only object whose emissivity is constant under different conditions.
Its temperature can be reliably estimated from its radiance. 1995-1999 TRW Inc.