colour.delta_E

colour.delta_E(a, b, method='CIE 2000', **kwargs)

Returns the difference \(\Delta E_{ab}\) between two given CIE L*a*b* or \(J'a'b'\) colourspace arrays using given method.

Parameters:

• a (array_like) – CIE L*a*b* or \(J'a'b'\) colourspace array \(a\).
• b (array_like) – CIE L*a*b* or \(J'a'b'\) colourspace array \(b\).
• method (unicode, optional) – {‘CIE 2000’, ‘CIE 1976’, ‘CIE 1994’, ‘CMC’, ‘CAM02-LCD’, ‘CAM02-SCD’, ‘CAM02-UCS’, ‘CAM16-LCD’, ‘CAM16-SCD’, ‘CAM16-UCS’} Computation method.

Other Parameters:  

• textiles (bool, optional) – {colour.difference.delta_E_CIE1994(), colour.difference.delta_E_CIE2000()}, Textiles application specific parametric factors \(k_L=2,\ k_C=k_H=1,\ k_1=0.048,\ k_2=0.014\) weights are used instead of \(k_L=k_C=k_H=1,\ k_1=0.045,\ k_2=0.015\).
• l (numeric, optional) – {colour.difference.delta_E_CIE2000()}, Lightness weighting factor.
• c (numeric, optional) – {colour.difference.delta_E_CIE2000()}, Chroma weighting factor.

Returns:

Colour difference \(\Delta E_{ab}\).

Return type:

numeric or ndarray

Examples

>>> import numpy as np
>>> a = np.array([100.00000000, 21.57210357, 272.22819350])
>>> b = np.array([100.00000000, 426.67945353, 72.39590835])
>>> delta_E(a, b)  
94.0356490...
>>> delta_E(a, b, method='CIE 2000')  
94.0356490...
>>> delta_E(a, b, method='CIE 1976')  
451.7133019...
>>> delta_E(a, b, method='CIE 1994')  
83.7792255...
>>> delta_E(a, b, method='CIE 1994', textiles=False)
... 
83.7792255...
>>> a = np.array([54.90433134, -0.08450395, -0.06854831])
>>> b = np.array([54.90433134, -0.08442362, -0.06848314])
>>> delta_E(a, b, method='CAM02-UCS')  
0.0001034...
>>> delta_E(a, b, method='CAM16-LCD')  
0.0001034...