colour.excitation_purity¶
- colour.excitation_purity(xy: ArrayLike, xy_n: ArrayLike, cmfs: Optional[colour.colorimetry.spectrum.MultiSpectralDistributions] = None) FloatingOrNDArray [source]¶
Return the excitation purity \(P_e\) for given colour stimulus \(xy\).
- Parameters
xy (ArrayLike) – Colour stimulus CIE xy chromaticity coordinates.
xy_n (ArrayLike) – Achromatic stimulus CIE xy chromaticity coordinates.
cmfs (Optional[colour.colorimetry.spectrum.MultiSpectralDistributions]) – Standard observer colour matching functions, default to the CIE 1931 2 Degree Standard Observer.
- Returns
Excitation purity \(P_e\).
- Return type
np.floating
ornumpy.ndarray
References
[CIET14804b], [Erdb]
Examples
>>> from colour.colorimetry import MSDS_CMFS >>> cmfs = MSDS_CMFS['CIE 1931 2 Degree Standard Observer'] >>> xy = np.array([0.54369557, 0.32107944]) >>> xy_n = np.array([0.31270000, 0.32900000]) >>> excitation_purity(xy, xy_n, cmfs) 0.6228856...