colour.XYZ_to_hdr_IPT

colour.XYZ_to_hdr_IPT(XYZ, Y_s=0.2, Y_abs=100, method=u'Fairchild 2011')

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

Parameters:

• XYZ (array_like) – CIE XYZ tristimulus values.
• 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-IPT colourspace array.

Return type:

ndarray

Notes

• Input CIE XYZ tristimulus values needs to be adapted for CIE Standard Illuminant D Series D65.

References

• [FW10]
• [FC11]

Examples

>>> XYZ = np.array([0.96907232, 1.00000000, 1.12179215])
>>> XYZ_to_hdr_IPT(XYZ)  
array([ 93.5317473...,   1.8564156...,  -1.3292254...])
>>> XYZ_to_hdr_IPT(XYZ, method='Fairchild 2010')  
array([ 94.6592917...,   0.3804177...,  -0.2673118...])