frudawski

# speceval

The speceval function evaluates spectral power distribution(s) for several parameters.

Note: The function also evaluates the α-opic daylight equivalents, e.g. the Melanopic Equivalent Daylight Illuminance (MEDI). Since the spectral power distribution can also represent other photometric units, as e.g. the luminance, the return values are named with Y instead of I for illuminance – as Y represents the photometric unit in question – hence MEDI is given as MEDY.

Usage:

data = speceval(lam,spec)

Where:

Examples

Evaluate the spectral power distribution of standard illuminant ‘FL4’:

lam = 380:780;
spec = ciespec(lam,'FL4');
speceval(lam,spec)

Result:

ans =

scalar structure containing the fields:

X = 1.0911e+06
Y = 9.9966e+05
Z = 3.8800e+05
SC = 296.82
MC = 1133.4
LC = 1635.8
RH = 597.45
MEL = 418.30
sc_EDY = 3.6318e+05
mc_EDY = 7.7850e+05
lc_EDY = 1.0042e+06
rh_EDY = 4.1212e+05
MEDY = 3.1541e+05
Tcp = 2939.5
x = 0.4402
y = 0.4033
z = 0.1565
x10 = 0.4492
y10 = 0.3907
z10 = 0.1601
u = 0.2530
v = 0.3477
v_ = 0.5216
L = 69.703
a = 17.433
b = 42.993
C = 46.393
h = 67.928
Ra = 51.375
Rf = 56.838
duv = -7.4044e-04

Evaluate several spectral power distributions with resulting |Y| = 1000:

lam = 380:780;
spec = ciespec(lam,{'FL2','A','D65'},1000);
data = speceval(lam,spec)

Result:

data =

scalar structure containing the fields:

X =

991.46   1098.41    950.42

Y =

1000   1000   1000

Z =

673.15    355.87   1088.61

SC =

0.5083   0.2542   0.8173

MC =

1.2814   1.1743   1.4558

LC =

1.6160   1.6567   1.6289

RH =

0.9250   0.8308   1.4497

MEL =

0.7558   0.6575   1.3262

sc_EDY =

621.92    311.01   1000.00

mc_EDY =

880.17    806.60   1000.00

lc_EDY =

992.05   1017.06   1000.00

rh_EDY =

638.04    573.09   1000.00

MEDY =

569.90    495.81   1000.00

Tcp =

4225.1   2856.0   6501.8

x =

0.3721   0.4475   0.3127

y =

0.3753   0.4075   0.3291

z =

0.2526   0.1450   0.3582

x10 =

0.3793   0.4511   0.3138

y10 =

0.3673   0.4059   0.3310

z10 =

0.2534   0.1429   0.3552

u =

0.2202   0.2560   0.1978

v =

0.3331   0.3495   0.3122

v_ =

0.4997   0.5243   0.4684

L =

67.672   69.997   64.084

a =

5.1118e+00   1.8313e+01  -5.7970e-03

b =

2.1367e+01   4.6138e+01   9.2311e-03

C =

2.1970e+01   4.9639e+01   1.0900e-02

h =

76.545    68.351   122.128

Ra =

64.250   100.000   100.000

Rf =

70.208   99.996   99.997

duv =

1.8626e-03   7.1936e-06   3.2145e-03

References

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

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).

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).

David Lewis MacAdam: Projective Transformations of I. C. I. Color Specifications. In: Journal of the Optical Society of America, vol. 27, no. 8, pp. 294-299, 1937, (DOI: 10.1364/JOSA.27.000294).

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.

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.