colour.HelmholtzKohlrausch_effect_luminous_Nayatani1997#

colour.HelmholtzKohlrausch_effect_luminous_Nayatani1997(uv: ArrayLike, uv_c: ArrayLike, L_a: ArrayLike, method: Literal['VAC', 'VCC'] | str = 'VCC') → NDArrayFloat[source]#

Return the HKE factor for luminous colours using Nayatani (1997) method.

Parameters:

uv (ArrayLike) – CIE uv chromaticity coordinates of samples.
uv_c (ArrayLike) – CIE uv chromaticity coordinates of reference white.
L_a (ArrayLike) – Adapting luminance in \(cd/m^2\).
method (Literal['VAC', 'VCC'] | str) – Which estimation method to use, VCC or VAC.

Returns:

Luminance factor (\(\Gamma\)) value(s) computed with Nayatani luminous colour estimation method.

Return type:

numpy.ndarray

References

[Nay97]

Examples

>>> import colour
>>> white = colour.xy_to_Luv_uv(colour.temperature.CCT_to_xy_CIE_D(6504))
>>> colours = colour.XYZ_to_xy(
...     [colour.wavelength_to_XYZ(430 + i * 50) for i in range(5)]
... )
>>> L_adapting = 65
>>> HelmholtzKohlrausch_effect_luminous_Nayatani1997(  
...     colour.xy_to_Luv_uv(colours), white, L_adapting
... )
array([ 7.4460471...,  2.4767159...,  1.4723422...,  0.7938695...,  4.1828629...])