colour.XYZ_to_Nayatani95

colour.XYZ_to_Nayatani95(XYZ, XYZ_n, Y_o, E_o, E_or, n=1)[source]

Computes the Nayatani (1995) colour appearance model correlates.

Parameters:
  • XYZ (array_like) – CIE XYZ tristimulus values of test sample / stimulus.
  • XYZ_n (array_like) – CIE XYZ tristimulus values of reference white.
  • Y_o (numeric or array_like) – Luminance factor \(Y_o\) of achromatic background as percentage normalised to domain [0.18, 1.0] in ‘Reference’ domain-range scale.
  • E_o (numeric or array_like) – Illuminance \(E_o\) of the viewing field in lux.
  • E_or (numeric or array_like) – Normalising illuminance \(E_{or}\) in lux usually normalised to domain [1000, 3000].
  • n (numeric or array_like, optional) – Noise term used in the non linear chromatic adaptation model.
Returns:

Nayatani (1995) colour appearance model specification.

Return type:

Nayatani95_Specification

Notes

Domain Scale - Reference Scale - 1
XYZ [0, 100] [0, 1]
XYZ_n [0, 100] [0, 1]
Range Scale - Reference Scale - 1
Nayatani95_Specification.h [0, 360] [0, 1]

References

[Fairchild2013ba], [Nayatani1995a]

Examples

>>> XYZ = np.array([19.01, 20.00, 21.78])
>>> XYZ_n = np.array([95.05, 100.00, 108.88])
>>> Y_o = 20.0
>>> E_o = 5000.0
>>> E_or = 1000.0
>>> XYZ_to_Nayatani95(XYZ, XYZ_n, Y_o, E_o, E_or)  # doctest: +ELLIPSIS
Nayatani95_Specification(L_star_P=49.9998829..., C=0.0133550..., h=257.5232268..., s=0.0133550..., Q=62.6266734..., M=0.0167262..., H=None, HC=None, L_star_N=50.0039154...)