colour.chromatic_adaptation¶

colour.chromatic_adaptation(XYZ, XYZ_w, XYZ_wr, method='Von Kries', **kwargs)[source]¶

Adapts given stimulus from test viewing conditions to reference viewing conditions.

Parameters

XYZ (array_like) – CIE XYZ tristimulus values of stimulus to adapt.
XYZ_w (array_like) – Test viewing condition CIE XYZ tristimulus values of the whitepoint.
XYZ_wr (array_like) – Reference viewing condition CIE XYZ tristimulus values of the whitepoint.
method (unicode, optional) – {‘Von Kries’, ‘CIE 1994’, ‘CMCCAT2000’, ‘Fairchild 1990’}, Computation method.

Other Parameters

E_o1 (numeric) – {colour.adaptation.chromatic_adaptation_CIE1994()}, Test illuminance \(E_{o1}\) in \(cd/m^2\).
E_o2 (numeric) – {colour.adaptation.chromatic_adaptation_CIE1994()}, Reference illuminance \(E_{o2}\) in \(cd/m^2\).
L_A1 (numeric or array_like) – {colour.adaptation.chromatic_adaptation_CMCCAT2000()}, Luminance of test adapting field \(L_{A1}\) in \(cd/m^2\).
L_A2 (numeric or array_like) – {colour.adaptation.chromatic_adaptation_CMCCAT2000()}, Luminance of reference adapting field \(L_{A2}\) in \(cd/m^2\).
Y_n (numeric or array_like) – {colour.adaptation.chromatic_adaptation_Fairchild1990()}, Luminance \(Y_n\) of test adapting stimulus in \(cd/m^2\).
Y_o (numeric) – {colour.adaptation.chromatic_adaptation_CIE1994()}, Luminance factor \(Y_o\) of achromatic background normalised to domain [0.18, 1] in ‘Reference’ domain-range scale.
direction (unicode, optional) – {colour.adaptation.chromatic_adaptation_CMCCAT2000()}, {‘Forward’, ‘Inverse’}, Chromatic adaptation direction.
discount_illuminant (bool, optional) – {colour.adaptation.chromatic_adaptation_Fairchild1990()}, Truth value indicating if the illuminant should be discounted.
n (numeric, optional) – {colour.adaptation.chromatic_adaptation_CIE1994()}, Noise component in fundamental primary system.
surround (CMCCAT2000_InductionFactors, optional) – {colour.adaptation.chromatic_adaptation_CMCCAT2000()}, Surround viewing conditions induction factors.
transform (unicode, optional) – {colour.adaptation.chromatic_adaptation_VonKries()}, {‘CAT02’, ‘XYZ Scaling’, ‘Von Kries’, ‘Bradford’, ‘Sharp’, ‘Fairchild’, ‘CMCCAT97’, ‘CMCCAT2000’, ‘CAT02_BRILL_CAT’, ‘Bianco’, ‘Bianco PC’}, Chromatic adaptation transform.

Returns

CIE XYZ_c tristimulus values of the stimulus corresponding colour.

Return type

ndarray

Notes

Domain	Scale - Reference	Scale - 1
`XYZ`	[0, 1]	[0, 1]
`XYZ_w`	[0, 1]	[0, 1]
`XYZ_wr`	[0, 1]	[0, 1]
`Y_o`	[0, 1]	[0, 1]

Range	Scale - Reference	Scale - 1
`XYZ_c`	[0, 1]	[0, 1]

References

[CIET13294], [Fai91], [Fai13c], [Fai13b], [LLRH02], [WRC12a]

Examples

Von Kries chromatic adaptation:

>>> import numpy as np
>>> XYZ = np.array([0.20654008, 0.12197225, 0.05136952])
>>> XYZ_w = np.array([0.95045593, 1.00000000, 1.08905775])
>>> XYZ_wr = np.array([0.96429568, 1.00000000, 0.82510460])
>>> chromatic_adaptation(XYZ, XYZ_w, XYZ_wr)
... 
array([ 0.2163881...,  0.1257    ,  0.0384749...])

CIE 1994 chromatic adaptation, requires extra kwargs:

>>> XYZ = np.array([0.2800, 0.2126, 0.0527])
>>> XYZ_w = np.array([1.09867452, 1.00000000, 0.35591556])
>>> XYZ_wr = np.array([0.95045593, 1.00000000, 1.08905775])
>>> Y_o = 0.20
>>> E_o = 1000
>>> chromatic_adaptation(
...     XYZ, XYZ_w, XYZ_wr, method='CIE 1994', Y_o=Y_o, E_o1=E_o, E_o2=E_o)
... 
array([ 0.2403379...,  0.2115621...,  0.1764301...])

CMCCAT2000 chromatic adaptation, requires extra kwargs:

>>> XYZ = np.array([0.2248, 0.2274, 0.0854])
>>> XYZ_w = np.array([1.1115, 1.0000, 0.3520])
>>> XYZ_wr = np.array([0.9481, 1.0000, 1.0730])
>>> L_A = 200
>>> chromatic_adaptation(
...     XYZ, XYZ_w, XYZ_wr, method='CMCCAT2000', L_A1=L_A, L_A2=L_A)
... 
array([ 0.1952698...,  0.2306834...,  0.2497175...])

Fairchild (1990) chromatic adaptation, requires extra kwargs:

>>> XYZ = np.array([0.1953, 0.2307, 0.2497])
>>> Y_n = 200
>>> chromatic_adaptation(
...     XYZ, XYZ_w, XYZ_wr, method='Fairchild 1990', Y_n=Y_n)
... 
array([ 0.2332526...,  0.2332455...,  0.7611593...])