"""
Common Colour Models Utilities
==============================
Defines various colour models common utilities:
- :attr:`colour.COLOURSPACE_MODELS`
- :func:`colour.models.Jab_to_JCh`
- :func:`colour.models.JCh_to_Jab`
- :func:`colour.models.XYZ_to_Iab`
- :func:`colour.models.Iab_to_XYZ`
References
----------
- :cite:`CIETC1-482004m` : CIE TC 1-48. (2004). CIE 1976 uniform colour
spaces. In CIE 015:2004 Colorimetry, 3rd Edition (p. 24).
ISBN:978-3-901906-33-6
"""
from __future__ import annotations
import numpy as np
from colour.algebra import cartesian_to_polar, polar_to_cartesian, vector_dot
from colour.hints import ArrayLike, Callable, NDArray, Tuple
from colour.utilities import (
CanonicalMapping,
attest,
from_range_1,
from_range_degrees,
to_domain_1,
to_domain_degrees,
tsplit,
tstack,
)
from colour.utilities.documentation import (
DocstringTuple,
is_documentation_building,
)
__author__ = "Colour Developers"
__copyright__ = "Copyright 2013 Colour Developers"
__license__ = "New BSD License - https://opensource.org/licenses/BSD-3-Clause"
__maintainer__ = "Colour Developers"
__email__ = "colour-developers@colour-science.org"
__status__ = "Production"
__all__ = [
"COLOURSPACE_MODELS",
"COLOURSPACE_MODELS_AXIS_LABELS",
"COLOURSPACE_MODELS_DOMAIN_RANGE_SCALE_1_TO_REFERENCE",
"Jab_to_JCh",
"JCh_to_Jab",
"XYZ_to_Iab",
"Iab_to_XYZ",
]
COLOURSPACE_MODELS: Tuple = (
"CAM02LCD",
"CAM02SCD",
"CAM02UCS",
"CAM16LCD",
"CAM16SCD",
"CAM16UCS",
"CIE XYZ",
"CIE xyY",
"CIE Lab",
"CIE Luv",
"CIE UCS",
"CIE UVW",
"DIN99",
"Hunter Lab",
"Hunter Rdab",
"ICaCb",
"ICtCp",
"IPT",
"IPT Munish 2021",
"IgPgTg",
"Jzazbz",
"OSA UCS",
"Oklab",
"hdr-CIELAB",
"hdr-IPT",
)
if is_documentation_building(): # pragma: no cover
COLOURSPACE_MODELS = DocstringTuple(COLOURSPACE_MODELS)
COLOURSPACE_MODELS.__doc__ = """
Colourspace models supporting a direct conversion to *CIE XYZ* tristimulus
values.
"""
COLOURSPACE_MODELS_AXIS_LABELS: CanonicalMapping = CanonicalMapping(
{
"CAM02LCD": ("$J^\\prime$", "$a^\\prime$", "$b^\\prime$"),
"CAM02SCD": ("$J^\\prime$", "$a^\\prime$", "$b^\\prime$"),
"CAM02UCS": ("$J^\\prime$", "$a^\\prime$", "$b^\\prime$"),
"CAM16LCD": ("$J^\\prime$", "$a^\\prime$", "$b^\\prime$"),
"CAM16SCD": ("$J^\\prime$", "$a^\\prime$", "$b^\\prime$"),
"CAM16UCS": ("$J^\\prime$", "$a^\\prime$", "$b^\\prime$"),
"CIE XYZ": ("X", "Y", "Z"),
"CIE xyY": ("x", "y", "Y"),
"CIE Lab": ("$L^*$", "$a^*$", "$b^*$"),
"CIE Luv": ("$L^*$", "$u^\\prime$", "$v^\\prime$"),
"CIE UCS": ("U", "V", "W"),
"CIE UVW": ("U", "V", "W"),
"DIN99": ("$L_{99}$", "$a_{99}$", "$b_{99}$"),
"Hunter Lab": ("$L^*$", "$a^*$", "$b^*$"),
"Hunter Rdab": ("Rd", "a", "b"),
"ICaCb": ("$I$", "$C_a$", "$C_b$"),
"ICtCp": ("$I$", "$C_T$", "$C_P$"),
"IPT": ("I", "P", "T"),
"IPT Munish 2021": ("I", "P", "T"),
"IgPgTg": ("$I_G$", "$P_G$", "$T_G$"),
"Jzazbz": ("$J_z$", "$a_z$", "$b_z$"),
"OSA UCS": ("L", "j", "g"),
"Oklab": ("$L$", "$a$", "$b$"),
"hdr-CIELAB": ("L hdr", "a hdr", "b hdr"),
"hdr-IPT": ("I hdr", "P hdr", "T hdr"),
}
)
"""Colourspace models labels mapping."""
attest(COLOURSPACE_MODELS == tuple(COLOURSPACE_MODELS_AXIS_LABELS.keys()))
COLOURSPACE_MODELS_DOMAIN_RANGE_SCALE_1_TO_REFERENCE: (
CanonicalMapping
) = CanonicalMapping(
{
"CAM02LCD": np.array([100, 100, 100]),
"CAM02SCD": np.array([100, 100, 100]),
"CAM02UCS": np.array([100, 100, 100]),
"CAM16LCD": np.array([100, 100, 100]),
"CAM16SCD": np.array([100, 100, 100]),
"CAM16UCS": np.array([100, 100, 100]),
"CIE XYZ": np.array([1, 1, 1]),
"CIE xyY": np.array([1, 1, 1]),
"CIE Lab": np.array([100, 100, 100]),
"CIE Luv": np.array([100, 100, 100]),
"CIE UCS": np.array([1, 1, 1]),
"CIE UVW": np.array([100, 100, 100]),
"DIN99": np.array([100, 100, 100]),
"Hunter Lab": np.array([100, 100, 100]),
"Hunter Rdab": np.array([100, 100, 100]),
"ICaCb": np.array([1, 1, 1]),
"ICtCp": np.array([1, 1, 1]),
"IPT": np.array([1, 1, 1]),
"IPT Munish 2021": np.array([1, 1, 1]),
"IgPgTg": np.array([1, 1, 1]),
"Jzazbz": np.array([1, 1, 1]),
"OSA UCS": np.array([100, 100, 100]),
"Oklab": np.array([1, 1, 1]),
"hdr-CIELAB": np.array([100, 100, 100]),
"hdr-IPT": np.array([100, 100, 100]),
}
)
"""Colourspace models domain-range scale **'1'** to **'Reference'** mapping."""
[docs]def Jab_to_JCh(Jab: ArrayLike) -> NDArray:
"""
Convert from *Jab* colour representation to *JCh* colour representation.
This definition is used to perform conversion from *CIE L\\*a\\*b\\**
colourspace to *CIE L\\*C\\*Hab* colourspace and for other similar
conversions. It implements a generic transformation from *Lightness*
:math:`J`, :math:`a` and :math:`b` opponent colour dimensions to the
correlates of *Lightness* :math:`J`, chroma :math:`C` and hue angle
:math:`h`.
Parameters
----------
Jab
*Jab* colour representation array.
Returns
-------
:class:`numpy.ndarray`
*JCh* colour representation array.
Notes
-----
+------------+-----------------------+-----------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+=================+
| ``Jab`` | ``J`` : [0, 100] | ``J`` : [0, 1] |
| | | |
| | ``a`` : [-100, 100] | ``a`` : [-1, 1] |
| | | |
| | ``b`` : [-100, 100] | ``b`` : [-1, 1] |
+------------+-----------------------+-----------------+
+------------+-----------------------+-----------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+=================+
| ``JCh`` | ``J`` : [0, 100] | ``J`` : [0, 1] |
| | | |
| | ``C`` : [0, 100] | ``C`` : [0, 1] |
| | | |
| | ``h`` : [0, 360] | ``h`` : [0, 1] |
+------------+-----------------------+-----------------+
References
----------
:cite:`CIETC1-482004m`
Examples
--------
>>> Jab = np.array([41.52787529, 52.63858304, 26.92317922])
>>> Jab_to_JCh(Jab) # doctest: +ELLIPSIS
array([ 41.5278752..., 59.1242590..., 27.0884878...])
"""
L, a, b = tsplit(Jab)
C, H = tsplit(cartesian_to_polar(tstack([a, b])))
JCh = tstack([L, C, from_range_degrees(np.degrees(H) % 360)])
return JCh
[docs]def JCh_to_Jab(JCh: ArrayLike) -> NDArray:
"""
Convert from *JCh* colour representation to *Jab* colour representation.
This definition is used to perform conversion from *CIE L\\*C\\*Hab*
colourspace to *CIE L\\*a\\*b\\** colourspace and for other similar
conversions. It implements a generic transformation from the correlates of
*Lightness* :math:`J`, chroma :math:`C` and hue angle :math:`h` to
*Lightness* :math:`J`, :math:`a` and :math:`b` opponent colour dimensions.
Parameters
----------
JCh
*JCh* colour representation array.
Returns
-------
:class:`numpy.ndarray`
*Jab* colour representation array.
Notes
-----
+-------------+-----------------------+-----------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+=============+=======================+=================+
| ``JCh`` | ``J`` : [0, 100] | ``J`` : [0, 1] |
| | | |
| | ``C`` : [0, 100] | ``C`` : [0, 1] |
| | | |
| | ``h`` : [0, 360] | ``h`` : [0, 1] |
+-------------+-----------------------+-----------------+
+-------------+-----------------------+-----------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+=============+=======================+=================+
| ``Jab`` | ``J`` : [0, 100] | ``J`` : [0, 1] |
| | | |
| | ``a`` : [-100, 100] | ``a`` : [-1, 1] |
| | | |
| | ``b`` : [-100, 100] | ``b`` : [-1, 1] |
+-------------+-----------------------+-----------------+
References
----------
:cite:`CIETC1-482004m`
Examples
--------
>>> JCh = np.array([41.52787529, 59.12425901, 27.08848784])
>>> JCh_to_Jab(JCh) # doctest: +ELLIPSIS
array([ 41.5278752..., 52.6385830..., 26.9231792...])
"""
L, C, H = tsplit(JCh)
a, b = tsplit(
polar_to_cartesian(tstack([C, np.radians(to_domain_degrees(H))]))
)
Jab = tstack([L, a, b])
return Jab
[docs]def XYZ_to_Iab(
XYZ: ArrayLike,
LMS_to_LMS_p_callable: Callable,
matrix_XYZ_to_LMS: ArrayLike,
matrix_LMS_p_to_Iab: ArrayLike,
) -> NDArray:
"""
Convert from *CIE XYZ* tristimulus values to *IPT*-like :math:`Iab` colour
representation.
This definition is used to perform conversion from *CIE XYZ* tristimulus
values to *IPT* colourspace and for other similar conversions. It
implements a generic transformation from *CIE XYZ* tristimulus values to
*Lightness* :math:`I`, :math:`a` and :math:`b` representing
red-green dimension, i.e. the dimension lost by protanopes and
the yellow-blue dimension, i.e. the dimension lost by tritanopes,
respectively.
Parameters
----------
XYZ
*CIE XYZ* tristimulus values.
LMS_to_LMS_p_callable
Callable applying the forward non-linearity to the :math:`LMS`
colourspace array.
matrix_XYZ_to_LMS
Matrix converting from *CIE XYZ* tristimulus values to :math:`LMS`
colourspace.
matrix_LMS_p_to_Iab
Matrix converting from non-linear :math:`LMS_p` colourspace to
*IPT*-like :math:`Iab` colour representation.
Returns
-------
:class:`numpy.ndarray`
*IPT*-like :math:`Iab` colour representation.
Notes
-----
+------------+-----------------------+-----------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+=================+
| ``XYZ`` | [0, 1] | [0, 1] |
+------------+-----------------------+-----------------+
+------------+-----------------------+-----------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+=================+
| ``Iab`` | ``I`` : [0, 1] | ``I`` : [0, 1] |
| | | |
| | ``a`` : [-1, 1] | ``a`` : [-1, 1] |
| | | |
| | ``b`` : [-1, 1] | ``b`` : [-1, 1] |
+------------+-----------------------+-----------------+
Examples
--------
>>> XYZ = np.array([0.20654008, 0.12197225, 0.05136952])
>>> LMS_to_LMS_p = lambda x: x**0.43
>>> M_XYZ_to_LMS = np.array(
... [
... [0.4002, 0.7075, -0.0807],
... [-0.2280, 1.1500, 0.0612],
... [0.0000, 0.0000, 0.9184],
... ]
... )
>>> M_LMS_p_to_Iab = np.array(
... [
... [0.4000, 0.4000, 0.2000],
... [4.4550, -4.8510, 0.3960],
... [0.8056, 0.3572, -1.1628],
... ]
... )
>>> XYZ_to_Iab(XYZ, LMS_to_LMS_p, M_XYZ_to_LMS, M_LMS_p_to_Iab)
... # doctest: +ELLIPSIS
array([ 0.3842619..., 0.3848730..., 0.1888683...])
"""
XYZ = to_domain_1(XYZ)
LMS = vector_dot(matrix_XYZ_to_LMS, XYZ)
LMS_p = LMS_to_LMS_p_callable(LMS)
Iab = vector_dot(matrix_LMS_p_to_Iab, LMS_p)
return from_range_1(Iab)
[docs]def Iab_to_XYZ(
Iab: ArrayLike,
LMS_p_to_LMS_callable: Callable,
matrix_Iab_to_LMS_p: ArrayLike,
matrix_LMS_to_XYZ: ArrayLike,
) -> NDArray:
"""
Convert from *IPT*-like :math:`Iab` colour representation to *CIE XYZ*
tristimulus values.
This definition is used to perform conversion from *IPT* colourspace to
*CIE XYZ* tristimulus values and for other similar conversions. It
implements a generic transformation from *Lightness* :math:`I`, :math:`a`
and :math:`b` representing red-green dimension, i.e. the dimension lost by
protanopes and the yellow-blue dimension, i.e. the dimension lost by
tritanopes, respectively to *CIE XYZ* tristimulus values.
Parameters
----------
Iab
*IPT*-like :math:`Iab` colour representation.
LMS_p_to_LMS_callable
Callable applying the reverse non-linearity to the :math:`LMS_p`
colourspace array.
matrix_Iab_to_LMS_p
Matrix converting from *IPT*-like :math:`Iab` colour representation to
non-linear :math:`LMS_p` colourspace.
matrix_LMS_to_XYZ
Matrix converting from :math:`LMS` colourspace to *CIE XYZ* tristimulus
values.
Returns
-------
:class:`numpy.ndarray`
*CIE XYZ* tristimulus values.
Notes
-----
+------------+-----------------------+-----------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+=================+
| ``Iab`` | ``I`` : [0, 1] | ``I`` : [0, 1] |
| | | |
| | ``a`` : [-1, 1] | ``a`` : [-1, 1] |
| | | |
| | ``b`` : [-1, 1] | ``b`` : [-1, 1] |
+------------+-----------------------+-----------------+
+------------+-----------------------+-----------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+=================+
| ``XYZ`` | [0, 1] | [0, 1] |
+------------+-----------------------+-----------------+
Examples
--------
>>> Iab = np.array([0.38426191, 0.38487306, 0.18886838])
>>> LMS_p_to_LMS = lambda x: x ** (1 / 0.43)
>>> M_Iab_to_LMS_p = np.linalg.inv(
... np.array(
... [
... [0.4000, 0.4000, 0.2000],
... [4.4550, -4.8510, 0.3960],
... [0.8056, 0.3572, -1.1628],
... ]
... )
... )
>>> M_LMS_to_XYZ = np.linalg.inv(
... np.array(
... [
... [0.4002, 0.7075, -0.0807],
... [-0.2280, 1.1500, 0.0612],
... [0.0000, 0.0000, 0.9184],
... ]
... )
... )
>>> Iab_to_XYZ(Iab, LMS_p_to_LMS, M_Iab_to_LMS_p, M_LMS_to_XYZ)
... # doctest: +ELLIPSIS
array([ 0.2065400..., 0.1219722..., 0.0513695...])
"""
Iab = to_domain_1(Iab)
LMS = vector_dot(matrix_Iab_to_LMS_p, Iab)
LMS_p = LMS_p_to_LMS_callable(LMS)
XYZ = vector_dot(matrix_LMS_to_XYZ, LMS_p)
return from_range_1(XYZ)