colour.difference.delta_E_CIE2000¶
-
colour.difference.
delta_E_CIE2000
(Lab_1, Lab_2, textiles=False)[source]¶ Returns the difference \(\Delta E_{ab}\) between two given CIE L*a*b* colourspace arrays using CIE 2000 recommendation.
Parameters: - Lab_1 (array_like) – CIE L*a*b* colourspace array 1.
- Lab_2 (array_like) – CIE L*a*b* colourspace array 2.
- textiles (bool, optional) – Textiles application specific parametric factors \(k_L=2,\ k_C=k_H=1\) weights are used instead of \(k_L=k_C=k_H=1\).
Returns: Colour difference \(\Delta E_{ab}\).
Return type: numeric or ndarray
Notes
- CIE 2000 colour differences are not symmetrical: difference between
Lab_1
andLab_2
may not be the same as difference betweenLab_2
andLab_1
thus one colour must be understood to be the reference against which a sample colour is compared. - Parametric factors \(k_L=k_C=k_H=1\) weights under
reference conditions:
- Illumination: D65 source
- Illuminance: 1000 lx
- Observer: Normal colour vision
- Background field: Uniform, neutral gray with \(L^*=50\)
- Viewing mode: Object
- Sample size: Greater than 4 degrees
- Sample separation: Direct edge contact
- Sample colour-difference magnitude: Lower than 5.0 \(\Delta E_{ab}\)
- Sample structure: Homogeneous (without texture)
References
Examples
>>> Lab_1 = np.array([100.00000000, 21.57210357, 272.22819350]) >>> Lab_2 = np.array([100.00000000, 426.67945353, 72.39590835]) >>> delta_E_CIE2000(Lab_1, Lab_2) 94.0356490... >>> Lab_2 = np.array([50.00000000, 426.67945353, 72.39590835]) >>> delta_E_CIE2000(Lab_1, Lab_2) 100.8779470... >>> delta_E_CIE2000(Lab_1, Lab_2, textiles=True) 95.7920535...