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# ciespec2xyz10

The ciespec2xyz10 function calculates the normalized CIE 1931 colour coordinates x,y,z for the 10 degree standard observer, for a given spectral power distribution (SPD). Any errors in the data set or in results generated from the reference data or the Lighting Toolbox are not in the liability of the CIE nor me, see license.

Usage:

[xyz10,x10,y10,z10,XYZ10] = ciespec2xyz10(lam,spec)

Where:

Note: For several input spectra use a row-wise matrix.

Note: For the determination of Tristimulus values XYZ one can also use the ciespec2unit function with reference ’xyz10’.

Examples

Determine the normalized Tristimulus values for standard illuminant ‘D65’:

lam = 360:830;
spec = ciespec(lam,'D65');
xyz10 = ciespec2xyz10(lam,spec)

Result:

xyz10 =

0.3138   0.3310   0.3552

Determine the normalized x and y component of the Tristimulus values for standard illuminant ‘D65’:

lam = 360:830;
spec = ciespec(lam,'D65');
[~,x10,y10] = ciespec2xyz10(lam,spec)
plotciexy(x10,y10)

Result:

x10 = 0.3138
y10 = 0.3310

Determine the normalized x and y component of the Tristimulus values for standard illuminants ‘A’ and ‘D65’:

lam = 360:830;
spec = ciespec(lam,{'A','D65'});
[~,x10,y10] = ciespec2xyz10(lam,spec)

Result:

x10 =

0.4511
0.3138

y10 =

0.4059
0.3310

Determine the Tristimulus values for standard illuminants ‘A’ and ‘D65’:

lam = 360:830;
spec = ciespec(lam,{'A','D65'});
[~,~,~,~,XYZ10] = ciespec2xyz10(lam,spec)

Result:

XYZ10 =

8.6372e+06   7.7717e+06   2.7360e+06
7.5249e+06   7.9367e+06   8.5165e+06

Note: The same results can be achieved with the ciespec2unit function:

lam = 360:830;
spec = ciespec(lam,{'A','D65'});
XYZ10 = ciespec2unit(lam,spec,'xyz10')

Result:

ᔀXYZ10 =

8.6372e+06   7.7717e+06   2.7360e+06
7.5249e+06   7.9367e+06   8.5165e+06

Reference

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