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:

Parameter | Description |

`medi` | Is the reurned melanopic equivalent daylight (‘D65’) quantity (MEDI). |

`lam` | Specifies the wavelengths. |

`spec` | Specifies the spectral power distribution (SPD). |

**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 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).`