Finally, where an animal is also sensitive to the UV region of the spectrum and there is a significant component of UV radiation, then an additional measure of the UV response should be included, as for the photopic rat and photopic mouse. for the scotopic cat, photopic rat and photopic mouse. Secondly, in a small number of cases where the sensitivity centres on the short to medium wavelengths, the CIE scotopic function should be used, e.g. Firstly, where the overall sensitivity is maximal in the medium to long wavelengths, the standard CIE photopic function will suffice, chicken, turkey and duck fall in this category. It differs from radiant flux, the measure of the total power of electromagnetic radiation (including infrared, ultraviolet, and visible light), in that luminous. Our results suggest that a judicial choice of three spectral sensitivity functions would satisfy most circumstances. It is also important to recognise that lighting-related parameters such as the good colour rendering of surfaces, the avoidance of glare from lamps and other factors that may be species related are sometimes of greater importance than the lighting levels. However, evidence is also presented that the magnitude of these inter-species effects are similar to, or smaller than, those arising from other optical, physiological and psychological factors, which are also likely to influence the resulting perception. Assuming that the resulting effects on retinal illuminance determine the overall perception of the level of light, there may be applications where these differences are important. The calculated lighting levels showed clear differences between species and the standard human. Calculations were made for spectral power distributions of daylight, incandescent light and 12 fluorescent sources commonly used to light interiors. Published spectral sensitivity data for a number of domesticated animals (human, turkey, duck, chicken, cat, rat and mouse) were used to calculate lighting levels for each species and compared with those derived from standard CIE human photopic and scotopic functions. Applications include the lighting of interior areas and the design of photometers. It does not contribute to the luminous flux.This paper considers whether photometric calculations using standard human spectral sensitivity data are satisfactory for applications with other species or whether it would be worthwhile to use bespoke spectral sensitivity functions for each species or group of species. (A lamp based on light emitting diodes (LEDs) may produce the same luminous flux with an electric consumption well below 10 W, because it has a much higher luminous efficacy.)Ī large living room requires several thousand lumen, corresponding to several of those lamps.Īlthough an incandescent lamp turns most of the consumed electrical power into thermal radiation, most of that radiation is in the infrared spectral region, where the luminosity function is zero, i.e., that light is not useful for illumination. It is a useful measure for how much a light source can contribute to the illumination of a room.įor example, a 60-W incandescent lamp may generate a luminous flux of 900 lm, corresponding to a luminous efficacy of 15 lm/W. The luminous flux is frequently found as a specification of light sources which are used for illumination purposes – for example, of incandescent lamps, fluorescent lamps and lamps based on LEDs. The luminous flux of a light source tells how much it contributes to the illumination of a room. This is the spectral response for reasonably high illumination intensities, where color vision works well. That quantity, however, does not take into account the sensitivity of the human eye.įor that, one has the photometric quantity luminous flux, specified with units of lumen (lm = cd sr), which takes into account the photopic response of the human eye. In radiometry, the radiant flux of a light source is its emitted optical energy per unit time. How to cite the article suggest additional literature from a light sourceĬategory: light detection and characterization Encyclopedia > letter L > luminous flux Luminous Fluxĭefinition: a measure of the perceived power of light, e.g.
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