Popis: |
Report presenting a unified approach to the specification of reflectance, in terms of both incident- and reflected- beam geometry. Nomenclature to facilitate this approach is proposed. Nomenclature for categorizing and specifying reflectance quantities for a variety of different beam configurations (both incident and reflected beams) is described, and all are defined and interrelated in terms of the bidirectional reflectance-distribution function. The conditions under which the formalism can be applied, including situations involving considerable sub-surface scattering, are carefully established. The entire treatment is limited to the domain of classical geometrical-optics radiometry and does not take into account interference and diffraction phenomena, such as are frequently encountered with highly coherent radiant flux. |