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 It might be outdated or ideologically biased.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.
References in periodicals archive ?
If the luminance factor a is too big, the output image will be very dark.
The last part of the abbreviation is the luminance factor and its two levels: high (H) and low (L).
The higher level of the luminance factor associated with a worse performance in RST, whereas the source size showed the same inverse effect: a lower working memory span was present at large source size scenarios.
For the combination of the task and luminance factors, there was a greater effect on the performance of RST at high luminance with a prosaccade task.
The luminance factor is calculated by measuring the average pixel value of the gray scale image for that block.
LIFE-SAVING BLAZE: Technically speaking, blaze orange, or "hunter orange" as it is just as commonly called, is defined as a daylight fluorescent orange color with a dominant wave length between 595 and 605 nanometers, excitation purity of not less than 85 percent and a luminance factor of not less than 40 percent, This means a hunter wearing it will stand out like a traffic cone among the greens, browns, tans and grays of nature.