The **ciecfi** function determines the general colour fidelity index R_{f}, the special colour fidelity indices R_{f,i}, the general chromaticity difference \text{d}E and the individual chromatic difference \text{d}E_i for a given test illuminant’s spectral power distribution. The procedure is described in CIE 224:2017. 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.

The procedure equals the revised ANSI TM30-20 standard method.

See also: plotcfi, plotcfibar

Usage:

[CFI,Rf] = ciecfi(lam,spec)

Where:

Parameter | Description |

`CFI` | Is the extended return struct containing the following fields:Rf: general colour fidelity indexRfi: 99 special colour rendering indices R_{f,i} for the 99 reference coloursTcp: Correlated Colour Temperature (CCT) T_{cp} of the test illuminantdE: chromaticity diffenrence \text{d}ECIECAM02UCS: contains the CIE CAM02-UCS colour apperance correlates J’, M’, a’ and b’ for the reference and test source, for TM30 plot, see plotcfi function.Duv: contains the delta uv distance of the test illuminant to a planck illuminant of the same correlated colour temperature, for TM30 plot, see plotcfi function. |

`Rf` | Returns the general colour fidelity index field for the illuminant(s). |

`lam` | Is a vector containing the wavelength steps. |

`spec` | Is a vector or matrix containing the spectral power distribution of the illuminant(s). For more than one spectrum use a row-wise data matrix. |

Note: several spectra can be used as input. In that case, the output struct contains for each field as many entries as input spectra. The individual fields of the CFI struct can be accessed using the dot notation:

To access the Rf field of the struct:

CFI.Rf

**Examples**

**Evaluate the colour fidelity index for CIE standard illuminant ‘LED-B1’:**

lam = 380:780; spec = ciespec(lam,'LED-B1'); CFI = ciecfi(lam,spec); Rf = CFI.Rf

See also: ciespec

Result:

Rf = 84.081

**Evaluate the colour fidelity index for CIE standard illuminant ‘FL1’ and plot the colour shift as in CIE 224:**

lam = 380:780; spec = ciespec(lam,'FL1'); CFI = ciecfi(lam,spec); plotcfi(CFI)

Result:

**Evaluate the colour fidelity index for CIE standard illuminant ‘FL4’ and plot the special colour rendering indices R_{f,i}:**

lam = 380:780; spec = ciespec(lam,'FL4'); CFI = ciecfi(lam,spec); plotcfibar(CFI)

See also: ciespec, plotcfibar

Result:

**Evaluate the special colour fidelity indeces for CIE standard illuminants ‘FL5’ and ‘LED-V1’:**

lam = 380:780; spec = ciespec(lam,{'FL5','LED-V1'}); CFI = ciecfi(lam,spec); CFI.Rfi

See also: ciespec

Result:

ans = 82.251 95.792 63.408 94.432 70.855 72.920 . . . 86.441 95.991 69.984 96.112 48.339 93.285

**Evaluate the general colour fidelity index R_{f,g} for CIE standard illuminants ‘FL5’ and ‘LED-V1’:**

lam = 380:780; spec = ciespec(lam,{'FL5','LED-V1'}); [~,Rfg] = ciecfi(lam,spec)

See also: ciespec

Result:

Rfg = 77.891 87.347

**Reference**

`CIE 2017 Colour Fidelity Index for accurate scientific use. Commission International de l’Éclairage (CIE), Vienna Austria, 2017, ISBN: 978-3-902842-61-9.`

`IES Method for Evaluating Light Source Color Rendition. Illuminating Engineering Society, Geneva, Switzerland, 2020, ISBN: 978-0-87995-379-9.`