| Concept definition: |
The ratio, for a particular material <SURFACE>, of the differential reflected <<RADIANCE>> into a unit solid angle about a particular (reflected) <DIRECTION> to the differential incident flux per unit surface <<AREA>> (irradiance) from a particular (incident) <DIRECTION>; bidirectional reflectance distribution function. This quantity, which is also known as directional-directional reflectance, is a function of the <<INCIDENCE_ZENITH_ANGLE_LOCAL>>, <<INCIDENCE_AZIMUTH_LOCAL>>, <<REFLECTANCE_ZENITH_ANGLE_LOCAL>>, and <<REFLECTANCE_AZIMUTH_LOCAL>>. This quantity is spectral (a distribution function in <<WAVELENGTH>>) and is measured in terms of inverse solid angle and inverse <<WAVELENGTH>> bin size. |
