frudawski

# cieedq

The cieedq function determines the \alpha-opic equivalent daylight (‘D65’) quantity for a given spectrum according to CIE S 026, e. g. the melanopic equivalent daylight illuminance (MEDI). 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:

edq = cieedq(lam,spec,'reference')

Where:

Examples

Melanopic equivalent daylight (‘D65’) illuminance (MEDI) of standard illuminant ‘A’ with a resulting illuminance of E = 100~\textrm{lx}:

lam = 380:780;
spec = ciespec(lam,'A');
% normalize to 100 lx
Y = ciespec2Y(lam,spec);
spec = 100./Y.*spec;
% determine MEDI value
medi = cieedq(lam,spec,'mel')

Result:

medi = 49.581

This means, with 49.6 lx of ‘D65’ daylight the same melanopic stimulus is achieved.

Determine \alpha-opic equivalent daylight (‘D65’) illuminances (EDI) of standard illuminant ‘FL12’ with a resulting illuminance of E = 100~\textrm{lx}:

lam = 380:780;
spec = ciespec(lam,'FL12');
% normalize to 100 lx
Y = ciespec2Y(lam,spec);
spec = 100./Y.*spec;
edi = cieedq(lam,spec,'aopic')

Result:

edi =

35.929    79.904   100.440    50.848    40.420

This means:

E_{v,sc}^{D65} = 35.929~\textrm{lx}

E_{v,mc}^{D65} = 79.904~\textrm{lx}

E_{v,lc}^{D65} = 100.440~\textrm{lx}

E_{v,rh}^{D65} = 50.848~\textrm{lx}

E_{v,mel}^{D65} = 40.420~\textrm{lx}

Reference:

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).