There is a distinct advantage to measuring temperature by detecting thermal radiation. The sensor
for thermal radiation need not be in contact with the surface to be measured, making this method
attractive for a wide variety of applications. The basic operation of a radiation thermometer is
predicated upon some knowledge of the radiation characteristics of the surface whose temperature is
being measured, relative to the calibration of the thermometer. The spectral characteristics of
radiative measurements of temperature is beyond the scope of the present discussion; an excellent
source for further information is Dewitt and Nutter