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kobavskytype

The kobavskytype function determines the CIE general standard sky type for a given luminance distribution of a Tregenza hemisphere as described by Kobav et al. in “Characterization of sky scanner measurements based on CIE and ISO standard CIE S 011/2003” .

See also: getskytype, tregenzaskytype

Usage:

[sky,RMS] = kobavskytype(L,sunaz,sunel,mode)

Where:

ParameterDescription
skyReturns the best fitting CIE standard general sky as in CIE S 011, determined with Kobav et al. method.
RMSReturns the Root Mean Square deviation from the best fitting CIE standard general sky. RMS from gradation and indicatrix determination is averaged.
LDefines the Tregenza hemisphere luminance distribution.
sunazDefines the sun azimuth angle \alpha_S.
sunelDefines the sun elevation angle \gamma_S.
mode
(optional)
Defines the luminance determination mode of the reference data:
’cie’ (default) returns the skytype according to the CIE table. Not all indicatrix and gradation goup combinations result in a skytype, the function will than return a NaN value.
’nearest’ returns the best fitting CIE skytpye.

Example

Determine CIE skytype at \alpha_S = 166\degree and \gamma_S = 33\degree:

L = ciesky(12,166,33);
[sky,RMS] = kobavskytype(L,166,33)

See also: ciesky

Result:

sky = 12
RMS = 0.019045

References

ISO 15469:2004(E)/CIE S 011/E:2003: Spatial Distribution of Daylight - CIE Standard General Sky. Commission Internationale de l'Éclairage (CIE), Vienna Austria, 2004.

Peter Roy Tregenza: Subdivision of the sky hemisphere for luminance measurements. In: Lighting Research and Technology, vol. 19, no. 1, pp. 13-14, 1987, (DOI: 10.1177/096032718701900103).

Kobav M, Bizjak G, Dumortier D.: Characterization of sky scanner measurements based on CIE and ISO standard CIE S 011/2003. In: Lighting Research & Technology, vol. 45, no. 4, pp. 504–512, 2012, (DOI: 10.1177/1477153512458916).

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