def test_nan_oetf_inverse_HLG_BT2100(self):
"""
Tests :func:`colour.models.rgb.transfer_functions.itur_bt_2100.\
oetf_inverse_HLG_BT2100` definition nan support.
"""
oetf_inverse_HLG_BT2100(
np.array([-1.0, 0.0, 1.0, -np.inf, np.inf, np.nan]))
def test_oetf_inverse_HLG_BT2100(self):
"""
Tests :func:`colour.models.rgb.transfer_functions.itur_bt_2100.\
oetf_inverse_HLG_BT2100` definition.
"""
self.assertAlmostEqual(oetf_inverse_HLG_BT2100(0.0), 0.0, places=7)
self.assertAlmostEqual(
oetf_inverse_HLG_BT2100(0.212132034355964), 0.18 / 12, places=7)
self.assertAlmostEqual(
oetf_inverse_HLG_BT2100(0.999999995536569), 1.0, places=7)
def test_domain_range_scale_oetf_inverse_HLG_BT2100(self):
"""
Tests :func:`colour.models.rgb.transfer_functions.itur_bt_2100.\
oetf_inverse_HLG_BT2100` definition domain and range scale support.
"""
E_p = 0.212132034355964
E = oetf_inverse_HLG_BT2100(E_p)
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_inverse_HLG_BT2100(E_p * factor),
E * factor,
decimal=7)
def test_n_dimensional_oetf_inverse_HLG_BT2100(self):
"""
Tests :func:`colour.models.rgb.transfer_functions.itur_bt_2100.\
oetf_inverse_HLG_BT2100` definition n-dimensional arrays support.
"""
E_p = 0.212132034355964
E = oetf_inverse_HLG_BT2100(E_p)
E_p = np.tile(E_p, 6)
E = np.tile(E, 6)
np.testing.assert_almost_equal(
oetf_inverse_HLG_BT2100(E_p), E, decimal=7)
E_p = np.reshape(E_p, (2, 3))
E = np.reshape(E, (2, 3))
np.testing.assert_almost_equal(
oetf_inverse_HLG_BT2100(E_p), E, decimal=7)
E_p = np.reshape(E_p, (2, 3, 1))
E = np.reshape(E, (2, 3, 1))
np.testing.assert_almost_equal(
oetf_inverse_HLG_BT2100(E_p), E, decimal=7)
def ICtCp_to_RGB(
ICtCp: ArrayLike,
method: Union[Literal["Dolby 2016", "ITU-R BT.2100-1 HLG",
"ITU-R BT.2100-1 PQ", "ITU-R BT.2100-2 HLG",
"ITU-R BT.2100-2 PQ", ], str, ] = "Dolby 2016",
L_p: Floating = 10000,
) -> NDArray:
"""
Convert from :math:`IC_TC_P` colour encoding to *ITU-R BT.2020*
colourspace.
Parameters
----------
ICtCp
:math:`IC_TC_P` colour encoding array.
method
Computation method. *Recommendation ITU-R BT.2100* defines multiple
variants of the :math:`IC_TC_P` colour encoding:
- *ITU-R BT.2100-1*
- *SMPTE ST 2084:2014* inverse electro-optical transfer
function (EOTF) and the :math:`IC_TC_P` matrix from
:cite:`Dolby2016a`: *Dolby 2016*, *ITU-R BT.2100-1 PQ*,
*ITU-R BT.2100-2 PQ* methods.
- *Recommendation ITU-R BT.2100* *Reference HLG* opto-electrical
transfer function (OETF) and the :math:`IC_TC_P` matrix
from :cite:`Dolby2016a`: *ITU-R BT.2100-1 HLG* method.
- *ITU-R BT.2100-2*
- *SMPTE ST 2084:2014* inverse electro-optical transfer
function (EOTF) and the :math:`IC_TC_P` matrix from
:cite:`Dolby2016a`: *Dolby 2016*, *ITU-R BT.2100-1 PQ*,
*ITU-R BT.2100-2 PQ* methods.
- *Recommendation ITU-R BT.2100* *Reference HLG* opto-electrical
transfer function (OETF) and a custom :math:`IC_TC_P`
matrix from :cite:`InternationalTelecommunicationUnion2018`:
*ITU-R BT.2100-2 HLG* method.
L_p
Display peak luminance :math:`cd/m^2` for *SMPTE ST 2084:2014*
non-linear encoding. This parameter should stay at its default
:math:`10000 cd/m^2` value for practical applications. It is exposed so
that the definition can be used as a fitting function.
Returns
-------
:class:`numpy.ndarray`
*ITU-R BT.2020* colourspace array.
Warnings
--------
The underlying *SMPTE ST 2084:2014* transfer function is an absolute
transfer function.
Notes
-----
- The *ITU-R BT.2100-1 PQ* and *ITU-R BT.2100-2 PQ* methods are aliases
for the *Dolby 2016* method.
- The underlying *SMPTE ST 2084:2014* transfer function is an absolute
transfer function, thus the domain and range values for the *Reference*
and *1* scales are only indicative that the data is not affected by
scale transformations.
+------------+-----------------------+------------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+==================+
| ``ICtCp`` | ``I`` : [0, 1] | ``I`` : [0, 1] |
| | | |
| | ``CT`` : [-1, 1] | ``CT`` : [-1, 1] |
| | | |
| | ``CP`` : [-1, 1] | ``CP`` : [-1, 1] |
+------------+-----------------------+------------------+
+------------+-----------------------+------------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+==================+
| ``RGB`` | ``UN`` | ``UN`` |
+------------+-----------------------+------------------+
References
----------
:cite:`Dolby2016a`, :cite:`Lu2016c`
Examples
--------
>>> ICtCp = np.array([0.07351364, 0.00475253, 0.09351596])
>>> ICtCp_to_RGB(ICtCp) # doctest: +ELLIPSIS
array([ 0.4562052..., 0.0308107..., 0.0409195...])
>>> ICtCp = np.array([0.62567899, -0.01984490, 0.35911259])
>>> ICtCp_to_RGB(ICtCp, method='ITU-R BT.2100-2 HLG') # doctest: +ELLIPSIS
array([ 0.4562052..., 0.0308107..., 0.0409195...])
"""
ICtCp = as_float_array(ICtCp)
method = validate_method(
method,
[
"Dolby 2016",
"ITU-R BT.2100-1 HLG",
"ITU-R BT.2100-1 PQ",
"ITU-R BT.2100-2 HLG",
"ITU-R BT.2100-2 PQ",
],
)
is_hlg_method = "hlg" in method
is_BT2100_2_method = "2100-2" in method
LMS_p = (vector_dot(MATRIX_ICTCP_ICTCP_TO_LMS_P_HLG_BT2100_2, ICtCp) if
(is_hlg_method and is_BT2100_2_method) else vector_dot(
MATRIX_ICTCP_ICTCP_TO_LMS_P, ICtCp))
with domain_range_scale("ignore"):
LMS = (oetf_inverse_HLG_BT2100(LMS_p)
if is_hlg_method else eotf_ST2084(LMS_p, L_p))
RGB = vector_dot(MATRIX_ICTCP_LMS_TO_RGB, LMS)
return RGB