Should CIE 1976 and CAM16-UCS methods give equal results?

[senyai]

>>> from colour import  delta_E
>>> a = [100.00000000, 21.57210357, 272.22819350]
>>> b = [100.00000000, 426.67945353, 72.39590835]
>>> delta_E(a, b, method='CIE 1976')
451.71330197359117
>>> delta_E(a, b, method='CAM16-UCS')
451.71330197359117

[KelSolaar]

Hi @senyai,

I know it is confusing but both methods are indeed using Euclidean distance under the hood, however, the inputs should be different: You cannot use a Lab colour with CAM16-UCS but a J'a'b' array from the CAM16 CAM:

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

At some point, I will roll the power values of Huang et al. (2015) as described in #370 and the result will be different even with the same input.

[KelSolaar]

Closing this one for now @senyai, cheers :)