scattering indicatrix, <for a specified incident beam>
indicatrix of diffusion, <for a specified incident beam>
representation in space, in the form of a surface expressed in polar coordinates, of the angular distribution of (relative) radiant intensity or luminous intensity or of (relative) radiance or luminance of an element of the surface of a medium that diffuses by reflection or transmission
Note 1 to entry: For a narrow incident beam of radiation, it is convenient to represent the scattering indicatrix in Cartesian coordinates. If the angular distribution has rotational symmetry, a meridian section of the surface is sufficient.
Note 2 to entry: The term "indicatrix" is often used to denote, instead of the surface, the curve obtained in a similar manner in a plane normal to the element concerned.
Note 3 to entry: This entry was numbered 845-04-91 in IEC 60050-845:1987.
Note 4 to entry: This entry was numbered 17-572 in CIE S 017:2011.