Luminance Factor
luminance factor
[′lü·mə·nəns ‚fak·tər] (optics)
The ratio of the luminance of a body when illuminated and observed under certain conditions to that of a perfect diffuser under the same conditions.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.
Luminance Factor
the ratio of the luminance of a body at a certain point and in a given direction to the luminance of a perfect diffuser under the same conditions of illumination. A perfect diffuser is a diffuser whose luminance is the same in all directions and whose reflection coefficient is equal to unity.
The concept of the luminance factor pertains to radiation that is evaluated in either radiometric or photometric units. The respective symbols for the luminance factor are βe and βv; the symbol β may be used in either case.
In recent years, the luminance factor has come to be applied not only to the reflection of light but also to the transmission and scattering of light, as well as to thermal radiation.
REFERENCE
Shuba, Iu. A. “Fotometricheskie kharakteristiki veshchestva.” Optiko-mekhanicheskaia promyshlennost’, 1975, no. 12, pp. 7–9.The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
luminance factor
The ratio of the luminance of a surface or medium under specified conditions of incidence, observation, and light source to the luminance of a lossless, perfectly diffusing surface or medium under the same conditions.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.