Illumination Terms

Horizontal illuminance (H)

Illuminance on a horizontal plane. The horizontal illuminance on the surface of the area is used to determine the adaptive status of eyes within the vision field range, and is also taken as the viewing background to highlight targets (athletes and objects).


Vertical illuminance (V)

Illuminance on a vertical plane. The vertical illuminance includes the vertical illuminance both in the directions of main camera and auxiliary camera. The vertical illuminance is used to simulate the light illuminating onto the face and body of athlete, provide the optimal identification for the cameras and viewers and influence the modelling effect of the illuminated target.


Service illuminance

Average illuminance during one maintenance cycle of an installation averaged over the relevant area.

Note: The area may be either the whole area of the working plane in an interior or the working areas.


Maintenance factor

Ratio of the average illuminance or luminance on the specified surface after a certain period to the values on the values surface when the device is newly installed under the same conditions.


 Main camera (MAI)

It is the fixed camera used to film the important zones in the total area or principal area


Auxiliary camera (AUX)

It is the fixed or mobile camera excluding the main camera.


Uniformity of illuminance (U)

Ratio of minimum illuminance to maximum illuminance of a surface and ratio of minimum illuminance to average illuminance of a surface. Uniformity is used to control the variance of illuminance level on competition areas.


Uniformity gradients

The uniformity gradient is expressed with the ratio of the illuminance at a certain grid point to that at its eight adjacent grid points. It can be used to measure the rate of change of illuminance level for any calculated metric.


Field of play

The competition and auxiliary area enclosed with stand, wall, and fence.


Principal area (PA)

Actual playing area required for the sport. This is generally the marked out “field " or” court”.


Total area (TA)

Principal Area (PA) with an additional surrounding safety areas or zones, which may be used in play.


Competition area

Principal area or Total area where there is a competition.


Color rendering index

Measurement of the degree to which the psychophysical color of an object illuminated by the test illuminant conforms to that of the same object illuminated by the reference illuminant, suitable allowance having been made for the state of chromatic adaptation.


General color rendering index (RA)

Mean of the CIE 1974 special color rendering indices for a specified set of 8 test color samples, generally called as the “color rendering index".


Special color rendering index

Measure of the degree to which the psychophysical color of a CIE test color sample (sample 9 to 15 illuminated by the test illuminant conforms to that of the same sample illuminated by the reference illuminant, suitable allowance having been made for the state of chromatic adaptation.


Colour temperature

Temperature of a Planckian radiator whose radiation has the same chromaticity as that of a given stimulus. The color temperature is used to represent that one kind of lighting takes on warm (red) or cold (blue) feeling or apparent sensation.


Correlated color temperature (TK or TCP)

Temperature of the Planckian radiator having the chromaticity nearest the chromaticity associated with the given spectral distribution on a diagram where the (CIE 1931standard observer based) u’, 2/3 v' coordinates of the Planckian locus and the test stimulus are depicted.



Property of a color stimulus defined by its chromaticity coordinates, or by its dominant or complementary wavelength and purity taken together.


Chromaticity coordinates

Ratio of each of a set of 3 tristimulus values to their sum.  In the X, Y, Z color system, the chromaticity coordinates x, y, z may be calculated by the tristimulus values.


Chromaticity tolerances (SDCM)

Color differences between chromaticity of each one in a batch of light sources and their rated chromaticity, expressed as the standard deviation of color matching.


Beam angle

Angle between the two vectors of the luminous intensity curve in polar coordinates in each plan. The luminous intensity of above two vectors is equal to 10% of the maximum luminous intensity.


Aiming angle

Angle between the peak light intensity direction and the downward vertical line of luminaire during the lighting design and installation.



Vision phenomenon in which there is discomfort or a reduction in the ability to see details or objects, caused by an unsuitable distribution or range of luminance, or by extreme contrasts.


Glare rating (GR)

Psychological physical parameter used to measure the subjective response to the discomfort sensation of eyes caused by the lighting devices in the outdoor or indoor sports halls and other outdoor areas.


TV emergency lighting

Lighting provided for competitions and television broadcasting continuously when the power supply to the normal electric lighting fails.


Light emitting diode lamp

Lamp that uses an electrical luminescence semiconductor as light source.

Light-emitting diode product that is assembled into a lamp for use in lighting fixtures.

 Stroboscopic effect

Visual phenomenon that human observes such object movement that shows difference from the actual movement of this object under the illumination with a certain frequency variation.

 Percent flicker

Relative amplitude of the periodic fluctuation of the luminous flux as measured by the ratio of the difference between the maximum and the minimum instantaneous luminous flux to the sum of both values, expressed as a percentage.

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