def test_n_dimensional_oetf_ST2084(self):
"""
Tests :func:`colour.models.rgb.transfer_functions.st_2084.\
oetf_ST2084` definition n-dimensional arrays support.
"""
C = 0.18
N = 0.079420969944927
np.testing.assert_almost_equal(
oetf_ST2084(C),
N,
decimal=7)
C = np.tile(C, 6)
N = np.tile(N, 6)
np.testing.assert_almost_equal(
oetf_ST2084(C),
N,
decimal=7)
C = np.reshape(C, (2, 3))
N = np.reshape(N, (2, 3))
np.testing.assert_almost_equal(
oetf_ST2084(C),
N,
decimal=7)
C = np.reshape(C, (2, 3, 1))
N = np.reshape(N, (2, 3, 1))
np.testing.assert_almost_equal(
oetf_ST2084(C),
N,
decimal=7)
def test_oetf_ST2084(self):
"""
Tests :func:`colour.models.rgb.transfer_functions.st_2084.\
oetf_ST2084` definition.
"""
self.assertAlmostEqual(
oetf_ST2084(0.0),
0.000000730955903,
places=7)
self.assertAlmostEqual(
oetf_ST2084(0.18),
0.079420969944927,
places=7)
self.assertAlmostEqual(
oetf_ST2084(1),
0.149945732100180,
places=7)
self.assertAlmostEqual(
oetf_ST2084(5000, 5000),
1.0,
places=7)
def test_nan_oetf_ST2084(self):
"""
Tests :func:`colour.models.rgb.transfer_functions.st_2084.\
oetf_ST2084` definition nan support.
"""
oetf_ST2084(
np.array([-1.0, 0.0, 1.0, -np.inf, np.inf, np.nan]))
def test_domain_range_scale_oetf_ST2084(self):
"""
Tests :func:`colour.models.rgb.transfer_functions.st_2084.\
oetf_ST2084` definition domain and range scale support.
"""
C = 100
N = oetf_ST2084(C)
d_r = (('reference', 1), (1, 1), (100, 100))
for scale, factor in d_r:
with domain_range_scale(scale):
np.testing.assert_almost_equal(oetf_ST2084(C * factor),
N * factor,
decimal=7)
def RGB_to_ICTCP(RGB, L_p=10000):
"""
Converts from *Rec. 2020* colourspace to :math:`IC_TC_P` colour encoding.
Parameters
----------
RGB : array_like
*Rec. 2020* colourspace array.
L_p : numeric, optional
Display peak luminance :math:`cd/m^2` for *SMPTE ST 2084:2014*
non-linear encoding.
Returns
-------
ndarray
:math:`IC_TC_P` colour encoding array.
Examples
--------
>>> RGB = np.array([0.35181454, 0.26934757, 0.21288023])
>>> RGB_to_ICTCP(RGB) # doctest: +ELLIPSIS
array([ 0.0955407..., -0.0089063..., 0.0138928...])
"""
LMS = dot_vector(ICTCP_RGB_TO_LMS_MATRIX, RGB)
LMS_p = oetf_ST2084(LMS, L_p)
ICTCP = dot_vector(ICTCP_LMS_P_TO_ICTCP_MATRIX, LMS_p)
return ICTCP
def oetf_BT2100_PQ(E):
"""
Defines *Recommendation ITU-R BT.2100* *Reference PQ* opto-electrical
transfer function (OETF / OECF).
The OETF maps relative scene linear light into the non-linear *PQ* signal
value.
Parameters
----------
E : numeric or array_like
:math:`E = {R_S, G_S, B_S; Y_S; or I_S}` is the signal determined by
scene light and scaled by camera exposure. The values :math:`E`,
:math:`R_S`, :math:`G_S`, :math:`B_S`, :math:`Y_S`, :math:`I_S` are in
the range [0, 1].
Returns
-------
numeric or ndarray
:math:`E` is the resulting non-linear signal (:math:`R'`, :math:`G'`,
:math:`B'`) in the range [0, 1].
References
----------
- :cite:`Borer2017a`
- :cite:`InternationalTelecommunicationUnion2016a`
Examples
--------
>>> oetf_BT2100_PQ(0.1) # doctest: +ELLIPSIS
0.7247698...
"""
return oetf_ST2084(ootf_BT2100_PQ(E), 10000)
def eotf_reverse_BT2100_PQ(F_D):
"""
Defines *Recommendation ITU-R BT.2100* *Reference PQ* reverse
electro-optical transfer function (EOTF / EOCF).
Parameters
----------
F_D : numeric or array_like
:math:`F_D` is the luminance of a displayed linear component
:math:`{R_D, G_D, B_D}` or :math:`Y_D` or :math:`I_D`, in
:math:`cd/m^2`.
Returns
-------
numeric or ndarray
:math:`E'` denotes a non-linear colour value :math:`{R', G', B'}` or
:math:`{L', M', S'}` in *PQ* space [0, 1].
References
----------
- :cite:`Borer2017a`
- :cite:`InternationalTelecommunicationUnion2016a`
Examples
--------
>>> eotf_reverse_BT2100_PQ(779.988360834085370) # doctest: +ELLIPSIS
0.7247698...
"""
return oetf_ST2084(F_D, 10000)
def RGB_to_ICTCP(RGB, L_p=10000):
"""
Converts from *ITU-R BT.2020* colourspace to :math:`IC_TC_P` colour
encoding.
Parameters
----------
RGB : array_like
*ITU-R BT.2020* colourspace array.
L_p : numeric, optional
Display peak luminance :math:`cd/m^2` for *SMPTE ST 2084:2014*
non-linear encoding.
Returns
-------
ndarray
:math:`IC_TC_P` colour encoding array.
Notes
-----
+------------+-----------------------+------------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+==================+
| ``RGB`` | [0, 1] | [0, 1] |
+------------+-----------------------+------------------+
+------------+-----------------------+------------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+==================+
| ``ICTCP`` | ``I`` : [0, 1] | ``I`` : [0, 1] |
| | | |
| | ``CT`` : [-1, 1] | ``CT`` : [-1, 1] |
| | | |
| | ``CP`` : [-1, 1] | ``CP`` : [-1, 1] |
+------------+-----------------------+------------------+
References
----------
:cite:`Dolby2016a`, :cite:`Lu2016c`
Examples
--------
>>> RGB = np.array([0.45620519, 0.03081071, 0.04091952])
>>> RGB_to_ICTCP(RGB) # doctest: +ELLIPSIS
array([ 0.0735136..., 0.0047525..., 0.0935159...])
"""
RGB = to_domain_1(RGB)
LMS = dot_vector(ICTCP_RGB_TO_LMS_MATRIX, RGB)
with domain_range_scale('ignore'):
LMS_p = oetf_ST2084(LMS, L_p)
ICTCP = dot_vector(ICTCP_LMS_P_TO_ICTCP_MATRIX, LMS_p)
return from_range_1(ICTCP)
def test_n_dimensional_oetf_ST2084(self):
"""
Tests :func:`colour.models.rgb.transfer_functions.st_2084.\
oetf_ST2084` definition n-dimensional arrays support.
"""
C = 100
N = oetf_ST2084(C)
C = np.tile(C, 6)
N = np.tile(N, 6)
np.testing.assert_almost_equal(oetf_ST2084(C), N, decimal=7)
C = np.reshape(C, (2, 3))
N = np.reshape(N, (2, 3))
np.testing.assert_almost_equal(oetf_ST2084(C), N, decimal=7)
C = np.reshape(C, (2, 3, 1))
N = np.reshape(N, (2, 3, 1))
np.testing.assert_almost_equal(oetf_ST2084(C), N, decimal=7)
def oetf_BT2100_PQ(E):
"""
Defines *Recommendation ITU-R BT.2100* *Reference PQ* opto-electrical
transfer function (OETF / OECF).
The OETF maps relative scene linear light into the non-linear *PQ* signal
value.
Parameters
----------
E : numeric or array_like
:math:`E = {R_S, G_S, B_S; Y_S; or I_S}` is the signal determined by
scene light and scaled by camera exposure.
Returns
-------
numeric or ndarray
:math:`E'` is the resulting non-linear signal (:math:`R'`, :math:`G'`,
:math:`B'`).
Notes
-----
+------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``E`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
+------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``E_p`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
References
----------
:cite:`Borer2017a`, :cite:`InternationalTelecommunicationUnion2016a`
Examples
--------
>>> oetf_BT2100_PQ(0.1) # doctest: +ELLIPSIS
0.7247698...
"""
return oetf_ST2084(ootf_BT2100_PQ(E), 10000)
def eotf_reverse_BT2100_PQ(F_D):
"""
Defines *Recommendation ITU-R BT.2100* *Reference PQ* reverse
electro-optical transfer function (EOTF / EOCF).
Parameters
----------
F_D : numeric or array_like
:math:`F_D` is the luminance of a displayed linear component
:math:`{R_D, G_D, B_D}` or :math:`Y_D` or :math:`I_D`, in
:math:`cd/m^2`.
Returns
-------
numeric or ndarray
:math:`E'` denotes a non-linear colour value :math:`{R', G', B'}` or
:math:`{L', M', S'}` in *PQ* space [0, 1].
Notes
-----
+------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``F_D`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
+------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``E_p`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
References
----------
:cite:`Borer2017a`, :cite:`InternationalTelecommunicationUnion2016a`
Examples
--------
>>> eotf_reverse_BT2100_PQ(779.988360834085370) # doctest: +ELLIPSIS
0.7247698...
"""
return oetf_ST2084(F_D, 10000)
def XYZ_to_JzAzBz(XYZ_D65, constants=JZAZBZ_CONSTANTS):
"""
Converts from *CIE XYZ* tristimulus values to :math:`J_zA_zB_z`
colourspace.
Parameters
----------
XYZ_D65 : array_like
*CIE XYZ* tristimulus values under
*CIE Standard Illuminant D Series D65*.
constants : Structure, optional
:math:`J_zA_zB_z` colourspace constants.
Returns
-------
ndarray
:math:`J_zA_zB_z` colourspace array where :math:`J_z` is Lightness,
:math:`A_z` is redness-greenness and :math:`B_z` is
yellowness-blueness.
Notes
-----
+------------+-----------------------+------------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+==================+
| ``XYZ`` | [0, 1] | [0, 1] |
+------------+-----------------------+------------------+
+------------+-----------------------+------------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+==================+
| ``JzAzBz`` | ``Jz`` : [0, 1] | ``Jz`` : [0, 1] |
| | | |
| | ``Az`` : [-1, 1] | ``Az`` : [-1, 1] |
| | | |
| | ``Bz`` : [-1, 1] | ``Bz`` : [-1, 1] |
+------------+-----------------------+------------------+
References
----------
:cite:`Safdar2017`
Examples
--------
>>> XYZ = np.array([0.20654008, 0.12197225, 0.05136952])
>>> XYZ_to_JzAzBz(XYZ) # doctest: +ELLIPSIS
array([ 0.0053504..., 0.0092430..., 0.0052600...])
"""
X_D65, Y_D65, Z_D65 = tsplit(to_domain_1(XYZ_D65))
X_p_D65 = constants.b * X_D65 - (constants.b - 1) * Z_D65
Y_p_D65 = constants.g * Y_D65 - (constants.g - 1) * X_D65
XYZ_p_D65 = tstack([X_p_D65, Y_p_D65, Z_D65])
LMS = dot_vector(JZAZBZ_XYZ_TO_LMS_MATRIX, XYZ_p_D65)
with domain_range_scale('ignore'):
LMS_p = oetf_ST2084(LMS, 10000, constants)
I_z, A_z, B_z = tsplit(dot_vector(JZAZBZ_LMS_P_TO_IZAZBZ_MATRIX, LMS_p))
J_z = ((1 + constants.d) * I_z) / (1 + constants.d * I_z) - constants.d_0
JzAzBz = tstack([J_z, A_z, B_z])
return from_range_1(JzAzBz)
