frudawski

# ciespec

The ciespec function contains various reference spectra provided by the Commission International d’Éclairage (CIE – International Commission on Illumination). The reference data is sourced from the CIE and permission to use the data in the Lighting Toolbox was granted. Any errors in the data set or in results generated with the Lighting Toolbox are not in the liability of the CIE nor me, see licence.

Usage:

spec = ciespec(lam,'ref',Y,W)

Where:

For wavelength increments smaller than given in the reference, the function does a linear interpolation, as suggested by the CIE. It is also possible to assign multiple references in one function call by using a cell array:

spec = ciespec(lambda,{'ref1','ref2',...,'refx'})

Note: the spectra are returned row wise as a n \times m matrix, with n spectra and m wavelength steps.

Sensitivity functions references:

Standard illuminant references:

Other references:

Examples:

Plot Tristimulus functions \bar{x}, \bar{y} and \bar{z}:

lam = 380:780;
ref = ciespec(lam,'xyz');
plot(lam,ref)

Result:

Plot D65 spectrum:

lam = 360:830;
spec = ciespec(lam,'D65');
plotspec(lam,spec)

Note: plotspec plots only in the visible region from 380 nm to 780 nm.

Result:

Plot \mathbf{\alpha}-opic functions in shades of gray:

lam = 380:780;
ref = ciespec(lam,'a-opic');
c = colors(5,'S',zeros(5,1));
plotorder(lam,ref,c)
xlim([380 780])
legend('s_{sc}','s_{mc}','s_{lc}','s_{rh}','s_{mel}')
xlabel('\lambda in nm')
grid on

Result:

Plot CIE Colour Rendering Index (CRI) reference colours:

lam = 380:780;
spec = ciespec(lam,'CRI');
c = spec2srgb(lam,spec);
plotcolour(c)

Result:

Create spectral power distribution of standard illuminants ‘FL4’ and ‘FL8’ with resulting photometric value of |Y| = 10000:

lam = 380:780;
spec = ciespec(lam,{'FL4','FL8'},10000);
Y = ciespec2Y(lam,spec) 

Result:

Y =

1.0000e+04
1.0000e+04

Create spectral power distribution of standard illuminants ‘FL4’ and ‘FL8’ with different weighting functions and target values:

lam = 380:780;
spec = ciespec(lam,{'FL4','FL8'},[100 200],{'VL','mel'});
Y = ciespec2Y(lam,spec)
mel = ciespec2unit(lam,spec,'mel')

Result:

Y =

1.0000e+02
1.8729e+05

mel =

4.1844e-02
2.0000e+02

References

ISO/CIE 11664-1:2019(E): Colorimetry - Part 1: CIE standard colorimetric observers. Commission International de l’Éclairage (CIE), Vienna Austria, 2019.

ISO 11664-2:2007(E)/CIE S 014-2/E:2006: Colorimetry - Part 2: CIE standard illuminants. Commission International de l’Éclairage (CIE), Vienna Austria, 2007.

CIE 15:2018: Colorimetry, 4th Edition. Commission International de l’Éclairage (CIE), Vienna Austria, 2018, ISBN: 978-3-902842-13-8 , (DOI: 10.25039/TR.015.2018).

CIE S 026/E:2018: CIE System for Metrology of Optical Radiation for ipRGC-Influenced Responses to Light. Commission International de l’Éclairage (CIE), Vienna Austria, 2018, (DOI: 10.25039/S026.2018).

IEC 62471:2006/CIE S 009:2002: Photobiological safety of lamps and lamp systems / Sécurité photobiologique des lampes et des appareils utilisant des lampes (bilingual edition). Commission Internationale de l'Éclairage (CIE), Vienna Austria, 2002.

CIE 224:2017: CIE 2017 Colour Fidelity Index for accurate scientific use. Commission International de l’Éclairage (CIE), Vienna Austria, 2017, ISBN: 978-3-902842-61-9.

CIE 13.3:1995: Method of measuring and specifying colour rendering properties of light sources. Commission Internationale de l'Éclairage (CIE), Vienna Austria, 1995, ISBN: 978 3 900734 57 2.