To facilitate better understanding of lighting techniques, here I would like to list a few basic concepts commonly used in lighting such as luminous flux, illuminance, reflectance …
1 Luminous flux (Φ)
University the amount of light flux techniques used in lighting is measured in units of lumens (lm). A lumen of light, does not depend on its wavelength (color), corresponding to the brightness that human eyes perceive. Different human eye perceives light for different wavelengths, felt most strongly for the 555 nm wavelength.
2 The intensity (I) light intensity I, measured in units of candela (cd). It is of a light flux emitted per unit of space angle (steradian).
Candela is a basic unit used in measuring the parameters of the light source and is calculated as follows: 1 candela is the intensity that a light source emits 1 lumen isotropic in a special corner. A 1 candela light source emits 1 lumen on a 1 square meter area at a distance of one meter from the light source center. Can see light intensity decreases with distance from the light source. 1cd = 1lm / 1steradian.
3 Illuminance (E)
an illuminance E (in lux) is a quantity characterizing light flux per unit area. A deck area of 1m2 with a 1 candela light intensity will be 1 lux illuminance. 1lux = 1lm / 1m2
4 Brightness (L)
Brightness L is the intensity of a light source extended diffused light or a reflector of light. Brightness is a measure of the density characteristic of light intensity distribution I on a surface area S in a way to advance.
1nit = 1cd / 1m2 Reflectance (ρ)
Reflectance of a body is a measure of the ratio between the luminous flux reflected (Φr) of the object compared to its luminous flux (Φ).
ρ = Φr / Φ
5 absorption coefficient (α)
absorption coefficient of an object is a measure of the ratio between the luminous flux is absorbed (Φa) of the object than the optical information to its (Φ).
α = Φa / Φ
6 Distribution of spectrum
Distribution spectrum of the radiation spectrum performed visible region raised the relationship between the radiated power depends on the wavelength.
7 Color temperature (C)
color temperature (measured in Kelvin) is the color of the light source emits light. Color temperature is defined as the absolute temperature of a black object radiation like radiation spectrum of the radiation spectrum light source.
8 Color rendering color rendering is represented by the color rendering index (CRI) is between 0 and 100, described color rendering of objects to be illuminated in the human eye compared to its real color. The higher CRI color rendering greater capabilities.
9 The performance of the light performance of the lamp is a measure of the performance of the unit light source in lumens on Watt (LPW), the parameter determines the amount of light emitted when consumed one watt electrical energy.
10 The average survival time
period average life time that 50% of the burnt lamp uses (usually identified in the laboratory). The performance of the light performance of the lamp is a measure of the performance of the unit light source in lumens on Watt (LPW), the parameter determines the amount of light emitted when consumed one watt electrical energy. The average survival time period average life time that 50% of the burnt lamp uses (usually identified in the laboratory). The performance of the light performance of the lamp is a measure of the performance of the unit light source in lumens on Watt (LPW), the parameter determines the amount of light emitted when consumed one watt electrical energy. The average survival time period average life time that 50% of the burnt lamp uses (usually identified in the laboratory).
