colour.hdr_CIELab_to_XYZ

colour.hdr_CIELab_to_XYZ(Lab_hdr, illuminant=array([ 0.3127, 0.329 ]), Y_s=0.2, Y_abs=100, method='Fairchild 2011')[source]

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

Parameters:
  • Lab_hdr (array_like) – hdr-CIELAB colourspace array.
  • 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.
  • 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:

CIE XYZ tristimulus values.
Return type:

ndarray

Notes

Domain Scale - Reference Scale - 1
Lab_hdr

L_hdr : [0, 100]

a_hdr : [-100, 100]

b_hdr : [-100, 100]

L_hdr : [0, 1]

a_hdr : [-1, 1]

b_hdr : [-1, 1]
illuminant [0, 1] [0, 1]
Y_s [0, 1] [0, 1]
Range Scale - Reference Scale - 1
XYZ [0, 1] [0, 1]

References

[FW10], [FC11]

Examples

>>> Lab_hdr = np.array([51.87002062, 60.4763385, 32.14551912])
>>> hdr_CIELab_to_XYZ(Lab_hdr)  # doctest: +ELLIPSIS
array([ 0.2065400...,  0.1219722...,  0.0513695...])
>>> Lab_hdr = np.array([31.99621114, 128.00763036, 48.76952309])
>>> hdr_CIELab_to_XYZ(Lab_hdr, method='Fairchild 2010')
... # doctest: +ELLIPSIS
array([ 0.2065400...,  0.1219722...,  0.0513695...])