Glare (vision)
Because of this, some cars include mirrors with automatic anti-glare functions and in buildings, blinds or louvers are often used to protect occupants.
[2] In buildings, discomfort glare can originate from small artificial lights (e.g. ceiling fixtures) that have brightnesses that are significantly greater than their surrounding.
When the luminous source occupies a much greater portion of the visual field (e.g. daylit windows), discomfort caused by glare can be linked to a saturating effect.
Since observers will not always look directly at a bright illuminated source, discomfort glare usually arises when an observer is focusing on a visual task (e.g. a computer-screen) and the bright source is within their peripheral visual field.
[3] Disability glare impairs the vision of objects without necessarily causing discomfort.
Some types of eyeglasses can reduce glare that occurs because of the imperfections on the surface of the eye.
Discomfort glare has often been studied using psychophysics experiments, where the common methods have been the luminance adjustment and category rating procedures.
[8] were amongst the first to compared subjective assessments given by observers against physical measurements produced by a glare source.
[11][12] This occurs when the luminance range influences the final evaluation of glare given by the observer.
The International Commission on Illumination (CIE) defines glare as: "Visual conditions in which there is excessive contrast or an inappropriate distribution of light sources that disturbs the observer or limits the ability to distinguish details and objects".
It is basically the logarithm of the glare of all visible lamps, divided by the background lumination
is the Guth Position Index, which depends on the distance from the line of sight of the viewer.
The Daylight Glare Probability (DGP) is a measure glare from real daylight condition in side-lit room within the field of view from curtain position, not considering for artificial light.
It considers illuminance and luminance from glare sources to estimate the level of dissatisfaction.
The EN 17037 glare assessment helps designer to determine shading need, transmission of glazing if the DGP is higher than 0.4.
is the Guth Position Index, which depends on the distance from the line of sight of the viewer.
