| Concept definition: |
The ratio, for a particular material <SURFACE> and unit solid angle about a particular incident <DIRECTION>, of the reflected <<RADIANCE>> into the hemisphere above that <SURFACE> to the incident <<RADIANCE>>; directional hemispherical reflectivity. This quantity is also defined as the integral over the reflected hemisphere of the BRDF times the cosine of the angle between the surface normal and the reflection <DIRECTION> times the differential reflection solid angle. It is a function of the <<INCIDENCE_ZENITH_ANGLE_LOCAL>> and <<INCIDENCE_AZIMUTH_LOCAL>> of the incident <<RADIANCE>> and is spectral (a distribution function in <<WAVELENGTH>>), therefore the quantity is measured in terms of inverse <<WAVELENGTH>> bin size. |
