def test_nan_cartesian_to_polar(self):
"""
Tests :func:`colour.algebra.coordinates.transformations.\
cartesian_to_polar` definition nan support.
"""
cases = [-1.0, 0.0, 1.0, -np.inf, np.inf, np.nan]
cases = set(permutations(cases * 3, r=2))
for case in cases:
a_i = np.array(case)
cartesian_to_polar(a_i)
def Luv_to_LCHuv(Luv):
"""
Converts from *CIE Luv* colourspace to *CIE LCHuv* colourspace.
Parameters
----------
Luv : array_like
*CIE Luv* colourspace array.
Returns
-------
ndarray
*CIE LCHuv* colourspace array.
Notes
-----
- Input / output :math:`L^*` is in domain / range [0, 100].
Examples
--------
>>> Luv = np.array([37.9856291 , -28.80219593, -1.35800706])
>>> Luv_to_LCHuv(Luv) # doctest: +ELLIPSIS
array([ 37.9856291..., 28.8341927..., 182.6994640...])
"""
L, u, v = tsplit(Luv)
C, H = tsplit(cartesian_to_polar(tstack((u, v))))
LCHuv = tstack((L, C, np.degrees(H) % 360))
return LCHuv
def test_n_dimensional_cartesian_to_polar(self):
"""
Test :func:`colour.algebra.coordinates.transformations.\
cartesian_to_polar` definition n-dimensional arrays support.
"""
a_i = np.array([3, 1])
a_o = cartesian_to_polar(a_i)
a_i = np.tile(a_i, (6, 1))
a_o = np.tile(a_o, (6, 1))
np.testing.assert_almost_equal(cartesian_to_polar(a_i), a_o, decimal=7)
a_i = np.reshape(a_i, (2, 3, 2))
a_o = np.reshape(a_o, (2, 3, 2))
np.testing.assert_almost_equal(cartesian_to_polar(a_i), a_o, decimal=7)
def Lab_to_LCHab(Lab):
"""
Converts from *CIE Lab* colourspace to *CIE LCHab* colourspace.
Parameters
----------
Lab : array_like
*CIE Lab* colourspace array.
Returns
-------
ndarray
*CIE LCHab* colourspace array.
Notes
-----
- *Lightness* :math:`L^*` is in domain [0, 100].
Examples
--------
>>> Lab = np.array([37.98562910, -23.62907688, -4.41746615])
>>> Lab_to_LCHab(Lab) # doctest: +ELLIPSIS
array([ 37.9856291..., 24.0384542..., 190.5892337...])
"""
L, a, b = tsplit(Lab)
C, H = tsplit(cartesian_to_polar(tstack((a, b))))
LCHab = tstack((L, C, np.degrees(H) % 360))
return LCHab
def test_cartesian_to_polar(self):
"""
Tests :func:`colour.algebra.coordinates.transformations.\
cartesian_to_polar` definition.
"""
np.testing.assert_almost_equal(cartesian_to_polar(np.array([3, 1])),
np.array([3.16227766, 0.32175055]),
decimal=7)
np.testing.assert_almost_equal(cartesian_to_polar(np.array([-1, 9])),
np.array([9.05538514, 1.68145355]),
decimal=7)
np.testing.assert_almost_equal(cartesian_to_polar(
np.array([6.3434, -0.9345])),
np.array([6.41186508, -0.14626640]),
decimal=7)
def Luv_to_LCHuv(Luv):
"""
Converts from *CIE L\\*u\\*v\\** colourspace to *CIE L\\*C\\*Huv*
colourspace.
Parameters
----------
Luv : array_like
*CIE L\\*u\\*v\\** colourspace array.
Returns
-------
ndarray
*CIE L\\*C\\*Huv* colourspace array.
Notes
-----
+------------+-----------------------+-----------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+=================+
| ``Luv`` | ``L`` : [0, 100] | ``L`` : [0, 1] |
| | | |
| | ``u`` : [-100, 100] | ``u`` : [-1, 1] |
| | | |
| | ``v`` : [-100, 100] | ``v`` : [-1, 1] |
+------------+-----------------------+-----------------+
+------------+-----------------------+-----------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+=================+
| ``LCHuv`` | ``L`` : [0, 100] | ``L`` : [0, 1] |
| | | |
| | ``C`` : [0, 100] | ``C`` : [0, 1] |
| | | |
| | ``uv`` : [0, 360] | ``uv`` : [0, 1] |
+------------+-----------------------+-----------------+
References
----------
:cite:`CIETC1-482004m`
Examples
--------
>>> Luv = np.array([41.52787529, 96.83626054, 17.75210149])
>>> Luv_to_LCHuv(Luv) # doctest: +ELLIPSIS
array([ 41.5278752..., 98.4499795..., 10.3881634...])
"""
L, u, v = tsplit(Luv)
C, H = tsplit(cartesian_to_polar(tstack([u, v])))
LCHuv = tstack([L, C, from_range_degrees(np.degrees(H) % 360)])
return LCHuv
def Luv_to_LCHuv(Luv):
"""
Converts from *CIE L\\*u\\*v\\** colourspace to *CIE L\\*C\\*Huv*
colourspace.
Parameters
----------
Luv : array_like
*CIE L\\*u\\*v\\** colourspace array.
Returns
-------
ndarray
*CIE L\\*C\\*Huv* colourspace array.
Notes
-----
+------------+-----------------------+-----------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+=================+
| ``Luv`` | ``L`` : [0, 100] | ``L`` : [0, 1] |
| | | |
| | ``u`` : [-100, 100] | ``u`` : [-1, 1] |
| | | |
| | ``v`` : [-100, 100] | ``v`` : [-1, 1] |
+------------+-----------------------+-----------------+
+------------+-----------------------+-----------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+=================+
| ``LCHuv`` | ``L`` : [0, 100] | ``L`` : [0, 1] |
| | | |
| | ``C`` : [0, 100] | ``C`` : [0, 1] |
| | | |
| | ``uv`` : [0, 360] | ``uv`` : [0, 1] |
+------------+-----------------------+-----------------+
References
----------
:cite:`CIETC1-482004m`
Examples
--------
>>> Luv = np.array([41.52787529, 96.83626054, 17.75210149])
>>> Luv_to_LCHuv(Luv) # doctest: +ELLIPSIS
array([ 41.5278752..., 98.4499795..., 10.3881634...])
"""
L, u, v = tsplit(Luv)
C, H = tsplit(cartesian_to_polar(tstack([u, v])))
LCHuv = tstack([L, C, from_range_degrees(np.degrees(H) % 360)])
return LCHuv
def Lab_to_LCHab(Lab):
"""
Converts from *CIE L\\*a\\*b\\** colourspace to *CIE L\\*C\\*Hab*
colourspace.
Parameters
----------
Lab : array_like
*CIE L\\*a\\*b\\** colourspace array.
Returns
-------
ndarray
*CIE L\\*C\\*Hab* colourspace array.
Notes
-----
+------------+-----------------------+-----------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+=================+
| ``Lab`` | ``L`` : [0, 100] | ``L`` : [0, 1] |
| | | |
| | ``a`` : [-100, 100] | ``a`` : [-1, 1] |
| | | |
| | ``b`` : [-100, 100] | ``b`` : [-1, 1] |
+------------+-----------------------+-----------------+
+------------+-----------------------+-----------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+=================+
| ``LCHab`` | ``L`` : [0, 100] | ``L`` : [0, 1] |
| | | |
| | ``C`` : [0, 100] | ``C`` : [0, 1] |
| | | |
| | ``ab`` : [0, 360] | ``ab`` : [0, 1] |
+------------+-----------------------+-----------------+
References
----------
:cite:`CIETC1-482004m`
Examples
--------
>>> Lab = np.array([41.52787529, 52.63858304, 26.92317922])
>>> Lab_to_LCHab(Lab) # doctest: +ELLIPSIS
array([ 41.5278752..., 59.1242590..., 27.0884878...])
"""
L, a, b = tsplit(Lab)
C, H = tsplit(cartesian_to_polar(tstack([a, b])))
LCHab = tstack([L, C, from_range_degrees(np.degrees(H) % 360)])
return LCHab
def UCS_Luo2006_to_JMh_CIECAM02(Jpapbp, coefficients):
"""
Converts from one of the *Luo et alii (2006)* *CAM02-LCD*, *CAM02-SCD*, or
*CAM02-UCS* colourspaces :math:`J'a'b'` array to *CIECAM02* :math:`JMh`
correlates array.
Parameters
----------
Jpapbp : array_like
*Luo et alii (2006)* *CAM02-LCD*, *CAM02-SCD*, or *CAM02-UCS*
colourspaces :math:`J'a'b'` array.
coefficients : array_like
Coefficients of one of the *Luo et alii (2006)* *CAM02-LCD*,
*CAM02-SCD*, or *CAM02-UCS* colourspaces.
Returns
-------
ndarray
*CIECAM02* correlates array :math:`JMh`.
Examples
--------
>>> Jpapbp = np.array([54.90433134, -0.08450395, -0.06854831])
>>> UCS_Luo2006_to_JMh_CIECAM02(
... Jpapbp, COEFFICIENTS_UCS_LUO2006['CAM02-LCD'])
... # doctest: +ELLIPSIS
array([ 4.1731091...e+01, 1.0884217...e-01, 2.1904843...e+02])
"""
J_p, a_p, b_p = tsplit(Jpapbp)
_K_L, c_1, c_2 = tsplit(coefficients)
J = -J_p / (c_1 * J_p - 1 - 100 * c_1)
M_p, h = tsplit(cartesian_to_polar(tstack((a_p, b_p))))
M = (np.exp(M_p / (1 / c_2)) - 1) / c_2
return tstack((J, M, np.degrees(h) % 360))
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
def UCS_Luo2006_to_JMh_CIECAM02(Jpapbp: ArrayLike,
coefficients: ArrayLike) -> NDArray:
"""
Convert from one of the *Luo et al. (2006)* *CAM02-LCD*, *CAM02-SCD*, or
*CAM02-UCS* colourspaces :math:`J'a'b'` array to *CIECAM02* :math:`JMh`
correlates array.
Parameters
----------
Jpapbp
*Luo et al. (2006)* *CAM02-LCD*, *CAM02-SCD*, or *CAM02-UCS*
colourspaces :math:`J'a'b'` array.
coefficients
Coefficients of one of the *Luo et al. (2006)* *CAM02-LCD*,
*CAM02-SCD*, or *CAM02-UCS* colourspaces.
Returns
-------
:class:`numpy.ndarray`
*CIECAM02* correlates array :math:`JMh`.
Notes
-----
+------------+------------------------+------------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+========================+==================+
| ``Jpapbp`` | ``Jp`` : [0, 100] | ``Jp`` : [0, 1] |
| | | |
| | ``ap`` : [-100, 100] | ``ap`` : [-1, 1] |
| | | |
| | ``bp`` : [-100, 100] | ``bp`` : [-1, 1] |
+------------+------------------------+------------------+
+------------+------------------------+------------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+========================+==================+
| ``JMh`` | ``J`` : [0, 100] | ``J`` : [0, 1] |
| | | |
| | ``M`` : [0, 100] | ``M`` : [0, 1] |
| | | |
| | ``h`` : [0, 360] | ``h`` : [0, 1] |
+------------+------------------------+------------------+
Examples
--------
>>> Jpapbp = np.array([54.90433134, -0.08450395, -0.06854831])
>>> UCS_Luo2006_to_JMh_CIECAM02(
... Jpapbp, COEFFICIENTS_UCS_LUO2006['CAM02-LCD'])
... # doctest: +ELLIPSIS
array([ 4.1731091...e+01, 1.0884217...e-01, 2.1904843...e+02])
"""
J_p, a_p, b_p = tsplit(to_domain_100(Jpapbp))
_K_L, c_1, c_2 = tsplit(coefficients)
J = -J_p / (c_1 * J_p - 1 - 100 * c_1)
M_p, h = tsplit(cartesian_to_polar(tstack([a_p, b_p])))
M = np.expm1(M_p / (1 / c_2)) / c_2
JMh = tstack([
from_range_100(J),
from_range_100(M),
from_range_degrees(np.degrees(h) % 360),
])
return JMh
def UCS_Luo2006_to_JMh_CIECAM02(Jpapbp, coefficients):
"""
Converts from one of the *Luo et al. (2006)* *CAM02-LCD*, *CAM02-SCD*, or
*CAM02-UCS* colourspaces :math:`J'a'b'` array to *CIECAM02* :math:`JMh`
correlates array.
Parameters
----------
Jpapbp : array_like
*Luo et al. (2006)* *CAM02-LCD*, *CAM02-SCD*, or *CAM02-UCS*
colourspaces :math:`J'a'b'` array.
coefficients : array_like
Coefficients of one of the *Luo et al. (2006)* *CAM02-LCD*,
*CAM02-SCD*, or *CAM02-UCS* colourspaces.
Returns
-------
ndarray
*CIECAM02* correlates array :math:`JMh`.
Notes
-----
+------------+------------------------+--------------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+========================+====================+
| ``Jpapbp`` | ``Jp_1`` : [0, 100] | ``Jp_1`` : [0, 1] |
| | | |
| | ``ap_1`` : [-100, 100] | ``ap_1`` : [-1, 1] |
| | | |
| | ``bp_1`` : [-100, 100] | ``bp_1`` : [-1, 1] |
+------------+------------------------+--------------------+
+------------+------------------------+--------------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+========================+====================+
| ``JMh`` | ``J`` : [0, 100] | ``J`` : [0, 1] |
| | | |
| | ``M`` : [0, 100] | ``M`` : [0, 1] |
| | | |
| | ``h`` : [0, 360] | ``h`` : [0, 1] |
+------------+------------------------+--------------------+
Examples
--------
>>> Jpapbp = np.array([54.90433134, -0.08450395, -0.06854831])
>>> UCS_Luo2006_to_JMh_CIECAM02(
... Jpapbp, COEFFICIENTS_UCS_LUO2006['CAM02-LCD'])
... # doctest: +ELLIPSIS
array([ 4.1731091...e+01, 1.0884217...e-01, 2.1904843...e+02])
"""
J_p, a_p, b_p = tsplit(to_domain_100(Jpapbp))
_K_L, c_1, c_2 = tsplit(coefficients)
J = -J_p / (c_1 * J_p - 1 - 100 * c_1)
M_p, h = tsplit(cartesian_to_polar(tstack([a_p, b_p])))
M = (np.exp(M_p / (1 / c_2)) - 1) / c_2
JMh = tstack([
from_range_100(J),
from_range_100(M),
from_range_degrees(np.degrees(h) % 360)
])
return JMh
