colour.XYZ_to_hdr_CIELab

colour.XYZ_to_hdr_CIELab(XYZ, illuminant=array([ 0.3457, 0.3585]), Y_s=0.2, Y_abs=100, method=u'Fairchild 2011')[source]

Converts from CIE XYZ tristimulus values to hdr-CIELAB colourspace.

Parameters:
  • XYZ (array_like) – CIE XYZ tristimulus values.
  • illuminant (array_like, optional) – Reference illuminant xy chromaticity coordinates or CIE xyY colourspace array.
  • Y_s (numeric or array_like) – Relative luminance \(Y_s\) of the surround in domain [0, 1].
  • Y_abs (numeric or array_like) – Absolute luminance \(Y_{abs}\) of the scene diffuse white in \(cd/m^2\).
  • method (unicode, optional) – {‘Fairchild 2011’, ‘Fairchild 2010’}, Computation method.
Returns:

hdr-CIELAB colourspace array.

Return type:

ndarray

Notes

  • Conversion to polar coordinates to compute the chroma \(C_{hdr}\) and hue \(h_{hdr}\) correlates can be safely performed with colour.Lab_to_LCHab() definition.
  • Conversion to cartesian coordinates from the Lightness \(L_{hdr}\), chroma \(C_{hdr}\) and hue \(h_{hdr}\) correlates can be safely performed with colour.LCHab_to_Lab() definition.
  • Input CIE XYZ tristimulus values are in domain [0, math:infty].
  • Input illuminant xy chromaticity coordinates or CIE xyY colourspace array are in domain [0, \(\infty\)].

References

Examples

>>> XYZ = np.array([0.07049534, 0.10080000, 0.09558313])
>>> XYZ_to_hdr_CIELab(XYZ)  
array([ 26.4646106..., -24.613326 ...,  -4.8479681...])
>>> XYZ_to_hdr_CIELab(XYZ, method='Fairchild 2010')  
array([ 24.9020664..., -46.8312760..., -10.1427484...])