Unenhanced image represented by a diagonal line.
Unhenhanced infrared image
Visible image
When raw satellite imagery is displayed, areas with low (high) reflected solar energy or emitted Earth energy would contain low(high) brightness values. Since radiant exitance is proportional to temperature as stated in the Stefan-Boltzmann Law, clouds in the upper atmosphere with colder tops would appear relatively dark in raw thermal IR imagery . However, by meteorological convention, the relationship between emitted energy and brightness values are inverted for thermal IR imagery such that cold cloud tops and cold surfaces appear bright. Visible satellite imagery that displays reflected solar energy are not enhanced. There are satellite channels where both reflected and emitted energy are significant. In these cases, enhancement curves are either inverted or no ehnancement is performed.