ciemedi

The ciemedi function determines the melanopic equivalent daylight (‘D65’) illuminance for a given spectrum according to CIE S 026, see cieedq function for other \alpha-opic references. 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:

medi = ciemedi(lam,spec)

Where:

Example

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 = ciemedi(lam,spec)

See also: ciespec, ciespec2Y, cieedq

Result:

medi = 49.581

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

Melanopic equivalent daylight (‘D65’) illuminances (MEDI) of standard illuminant ‘A’, ‘D55’ and ‘FL12’ each with a resulting illuminance of E = 100~\textrm{lx}:

lam = 380:780;
spec = ciespec(lam,{'A','D55','FL12'});
% normalize to 100 lx
Y = ciespec2Y(lam,spec);
spec = 100./Y.*spec;
% determine MEDI value
medi = ciemedi(lam,spec)

See also: ciespec, ciespec2Y, cieedq

Result:

medi =

   49.581
   90.402
   40.420

Reference:

CIE S 026/E:2018: CIE System for Metrology of Optical Radiation for ipRGC-Influenced Responses to Light. Commission Internationale de l’Eclairage, Vienna Austria, 2018, DOI: 10.25039/S026.2018. URL: https://cie.co.at/publications/cie-system-metrology-optical-radiation-iprgc-influenced-responses-light-0