colour.OSA_UCS_to_XYZ#
- colour.OSA_UCS_to_XYZ(Ljg: ArrayLike, optimisation_kwargs: dict | None = None) NDArrayFloat [source]#
Convert from OSA UCS colourspace to CIE XYZ tristimulus values under the CIE 1964 10 Degree Standard Observer.
- Parameters:
Ljg (ArrayLike) – OSA UCS \(Ljg\) lightness, jaune (yellowness), and greenness.
optimisation_kwargs (dict | None) – Parameters for
scipy.optimize.fmin()
definition.
- Returns:
CIE XYZ tristimulus values under the CIE 1964 10 Degree Standard Observer.
- Return type:
Warning
There is no analytical inverse transformation from OSA UCS to \(Ljg\) lightness, jaune (yellowness), and greenness to CIE XYZ tristimulus values, the current implementation relies on optimization using
scipy.optimize.fmin()
definition and thus has reduced precision and poor performance.Notes
Domain
Scale - Reference
Scale - 1
Ljg
L
: [-100, 100]j
: [-100, 100]g
: [-100, 100]L
: [-1, 1]j
: [-1, 1]g
: [-1, 1]Range
Scale - Reference
Scale - 1
XYZ
[0, 100]
[0, 1]
OSA UCS uses the CIE 1964 10 Degree Standard Observer.
References
Examples
>>> import numpy as np >>> Ljg = np.array([-3.00499790, 2.99713697, -9.66784231]) >>> OSA_UCS_to_XYZ(Ljg) array([ 20.6540240..., 12.1972369..., 5.1369372...])