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(General Physics) the luminous flux incident on unit area of a surface. It is measured in lux. Symbol: Ev Sometimes called: illumination Compare irradiance


(ɪˌlu məˈneɪ ʃən)

1. an act or instance of illuminating.
2. the state of being illuminated.
3. a decoration of lights.
4. Sometimes, illuminations. a display using lights as a major decoration.
5. intellectual or spiritual enlightenment.
6. the intensity of light falling at a given place on a lighted surface; the luminous flux incident per unit area, expressed in lumens per unit of area.
7. a supply of light.
8. decoration of a manuscript or book with a painted design in color and gold or silver.
9. a design used in such decoration.
[1300–50; Middle English < Latin]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.illuminance - the luminous flux incident on a unit area
brightness level, luminance, luminosity, luminousness, brightness, light - the quality of being luminous; emitting or reflecting light; "its luminosity is measured relative to that of our sun"
References in periodicals archive ?
Measurement day and the outdoor diffuse and global horizontal illuminances and irradiances at each time step (five minutes).
The illuminance metric is a climate-based, whole-year metric calculated for each time period as a weighted average of illuminances from each sky type.
While not designed to compete with a professional meter, the new app will provide average illuminances in lux and footcandles, keep a running total of readings and average illuminance for a given space, and record a log of past readings.
In the first decades of the 20th century, the IES promulgated so-called "lighting codes" that described illuminances appropriate for various applications, including industry, offices, and schools [IES 1912; 1916; 1925; 1928].
The deviation in the user set levels was large with both of the tested lightings and there were indications that adjustment range affected to user set illuminances.
5, it will be allowable for designers to design to reduced illuminances, to maintain the same visual acuity as presumed in the IES Illuminance Determination System.
It would be beneficial to have a time- and cost-effective method to predict illuminances in the surgical site and to test if a virtual prototype of a surgical luminaire complies to [IEC 2009], before building the device.
Later, two advanced daylight metrics were brought into use: daylight autonomy (Reinhart, 2002; Tzempelikos and Athienitis, 2005, 2007) and useful daylight illuminances (Nabil and Mardaljevic, 2005, 2006; Shen and Tzempelikos, 2010).
Statistical analysis of the results did not indicate differences between illuminances ratios found using the six visual equality objectives to be significant.
The box plot in Figure 1 shows the range of desktop illuminances, with the workstations grouped by their distance from the window and window orientation.
Other sophisticated methods exist for control of venetian blinds and prediction of indoor illuminances based on correlations between calibrated interior sensors (Park and Athienitis 2003).
Luminances were extracted from these HDR pictures and those measured with the luminance meter were then weighted according to the horizontal illuminances recorded in the minor box.