eng
blackbody radiance
Ibb,v
physical radiance of an absorber determined by applying Planck's function (either in wavelength space or in terms of frequencies) to absorber temperature, , as shown in the following formula (in frequency space): where is the temperature of the absorber; is the Plank’s constant ( ); is the frequency in Hz; is the velocity of light ( ); is the Boltzmann’s constant ( ); is the base of natural logarithm.
Note to entry: The constants are defined in terms of a perfect blackbody.
[SOURCE: ISO/TS 19159-4:2022, 3.10]