# colour.models.cie_ucs Module¶

## CIE UCS Colourspace¶

Defines the CIE UCS colourspace transformations:

References

 [1] Wikipedia. (n.d.). CIE 1960 color space. Retrieved February 24, 2014, from http://en.wikipedia.org/wiki/CIE_1960_color_space
 [2] Wikipedia. (n.d.). Relation to CIE XYZ. Retrieved February 24, 2014, from http://en.wikipedia.org/wiki/CIE_1960_color_space#Relation_to_CIE_XYZ
colour.models.cie_ucs.XYZ_to_UCS(XYZ)[source]

Converts from CIE XYZ tristimulus values to CIE UCS colourspace.

Parameters: XYZ (array_like) – CIE XYZ tristimulus values. CIE UCS colourspace array. ndarray

Notes

• Input CIE XYZ tristimulus values are in domain [0, 1].
• Output CIE UCS colourspace array is in domain [0, 1].

Examples

>>> import numpy as np
>>> XYZ = np.array([0.07049534, 0.10080000, 0.09558313])
>>> XYZ_to_UCS(XYZ)
array([ 0.0469968...,  0.1008    ,  0.1637439...])

colour.models.cie_ucs.UCS_to_XYZ(UVW)[source]

Converts from CIE UCS colourspace to CIE XYZ tristimulus values.

Parameters: UVW (array_like) – CIE UCS colourspace array. CIE XYZ tristimulus values. ndarray

Notes

• Input CIE UCS colourspace array is in domain [0, 1].
• Output CIE XYZ tristimulus values are in domain [0, 1].

Examples

>>> import numpy as np
>>> UVW = np.array([0.04699689, 0.10080000, 0.16374390])
>>> UCS_to_XYZ(UVW)
array([ 0.0704953...,  0.1008    ,  0.0955831...])

colour.models.cie_ucs.UCS_to_uv(UVW)[source]

Returns the uv chromaticity coordinates from given CIE UCS colourspace array.

Parameters: UVW (array_like) – CIE UCS colourspace array. uv chromaticity coordinates. ndarray

Notes

• Input CIE UCS colourspace array is in domain [0, 1].
• Output uv chromaticity coordinates are in domain [0, 1].

Examples

>>> import numpy as np
>>> UCS = np.array([0.04699689, 0.10080000, 0.16374390])
>>> UCS_to_uv(UCS)
array([ 0.1508530...,  0.3235531...])

colour.models.cie_ucs.UCS_uv_to_xy(uv)[source]

Returns the xy chromaticity coordinates from given CIE UCS colourspace uv chromaticity coordinates.

Parameters: uv (array_like) – CIE UCS uv chromaticity coordinates. xy chromaticity coordinates. ndarray

Notes

• Input uv chromaticity coordinates are in domain [0, 1].
• Output xy chromaticity coordinates are in domain [0, 1].

Examples

>>> import numpy as np
>>> uv = np.array([0.15085308732766581, 0.3235531372954405])
>>> UCS_uv_to_xy(uv)
array([ 0.2641477...,  0.3777000...])