colour.XYZ_to_CIE1976UCS#

colour.XYZ_to_CIE1976UCS(XYZ: ArrayLike, illuminant: ArrayLike = CCS_ILLUMINANTS['CIE 1931 2 Degree Standard Observer']['D65']) NDArrayFloat[source]#

Convert from CIE XYZ tristimulus values to \(uv^pL\*\) colourspace.

This colourspace combines the \(uv^p\) chromaticity coordinates with the Lightness \(L\*\) from the CIE L*u*v* colourspace.

It is a convenient definition for use with the CIE 1976 UCS Chromaticity Diagram.

Parameters:
  • XYZ (ArrayLike) – CIE XYZ tristimulus values.

  • illuminant (ArrayLike) – Reference illuminant CIE xy chromaticity coordinates or CIE xyY colourspace array.

Returns:

\(uv^pL\*\) colourspace array.

Return type:

numpy.ndarray

Notes

Domain

Scale - Reference

Scale - 1

XYZ

[0, 1]

[0, 1]

illuminant

[0, 1]

[0, 1]

Range

Scale - Reference

Scale - 1

uvL

u : [-1, 1]

v : [-1, 1]

L : [0, 100]

u : [-1, 1]

v : [-1, 1]

L : [0, 1]

Examples

>>> import numpy as np
>>> XYZ = np.array([0.20654008, 0.12197225, 0.05136952])
>>> XYZ_to_CIE1976UCS(XYZ)  
array([  0.3772021...,   0.5012026...,  41.5278752...])