ABSTRACT
The equivalent differential temperature, Delta T, measurement has been used as a metric for target-to-background contrast by infrared weapons designers and analysts. It is defined as the equivalent differential temperature of two blackbody sources—target and background—which are required to provide the differential flux as that of the actual target and actual background. This entry covers the practical methods of measuring an apparent Delta T in the field and includes six different methods for calculation of an apparent Delta T.
