Visibility(redirected from visibilities)
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the possibility of visual perception of objects that are distant from the observer. Visibility is characterized by degrees—that is, distinguishability (how clearly the object can be seen)—and by range—that is, the distance at which the object under observation is no longer discernible to the naked eye. Visibility is classified according to the observation medium as atmospheric visibility (in the air), underwater visibility (in water), and visibility in solid bodies (for example, in glass). Generally, an object’s distinguishability depends on its angular dimensions, the brightness level, the contrast between the background and the object, the time of observation, the degree of pollution of the medium, and other technical and physiological factors. The determination of an object’s visibility is one of the principal tasks of human engineering that is related to the development of automatic control systems, which include reflection devices for the visual and rapid transmission of information to the human operator.
REFERENCESInzhenerno-psikhologicheskie trebovaniia k sistemam upravleniia. Moscow, 1961.
Woodson, W., and D. Conover. Spravochnik po inzhenernoi psikhologii dlia inzhenerov i khudozhnikov-konstruktorov. Moscow, 1968. (Translated from English.)
V. P. ISAEV
from an automobile, the extent to which an unobstructed view is provided of the area surrounding an automobile. Upward vision from the driver’s seat is determined by the limit of visibility for a point located 5 m above the road. Blowing warm air over the front windshield is an effective means of improving visibility for the driver in winter.
Rear visibility is determined by the size and location of the rear windshield; it can also be improved by the installation of additional rear-view mirrors and by heating the rear windshield in winter. Visibility is an important consideration in the design of vehicles and of machines used for hoisting and transportation.
M. B. AFANAS’EV