"""
ITU-R BT.709-6
==============
Defines the *ITU-R BT.709-6* opto-electrical transfer function (OETF)
and its inverse:
- :func:`colour.models.oetf_BT709`
- :func:`colour.models.oetf_inverse_BT709`
References
----------
- :cite:`InternationalTelecommunicationUnion2015i` : International
Telecommunication Union. (2015). Recommendation ITU-R BT.709-6 - Parameter
values for the HDTV standards for production and international programme
exchange BT Series Broadcasting service (pp. 1-32).
https://www.itu.int/dms_pubrec/itu-r/rec/bt/\
R-REC-BT.709-6-201506-I!!PDF-E.pdf
"""
from __future__ import annotations
from colour.hints import FloatingOrArrayLike, FloatingOrNDArray
from colour.models.rgb.transfer_functions import oetf_BT601, oetf_inverse_BT601
__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__ = [
"oetf_BT709",
"oetf_inverse_BT709",
]
[docs]def oetf_BT709(L: FloatingOrArrayLike) -> FloatingOrNDArray:
"""
Define *Recommendation ITU-R BT.709-6* opto-electronic transfer function
(OETF).
Parameters
----------
L
*Luminance* :math:`L` of the image.
Returns
-------
:class:`numpy.floating` or :class:`numpy.ndarray`
Corresponding electrical signal :math:`V`.
Notes
-----
+------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``L`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
+------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``V`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
References
----------
:cite:`InternationalTelecommunicationUnion2015i`
Examples
--------
>>> oetf_BT709(0.18) # doctest: +ELLIPSIS
0.4090077...
"""
return oetf_BT601(L)
[docs]def oetf_inverse_BT709(V: FloatingOrArrayLike) -> FloatingOrNDArray:
"""
Define *Recommendation ITU-R BT.709-6* inverse opto-electronic transfer
function (OETF).
Parameters
----------
V
Electrical signal :math:`V`.
Returns
-------
:class:`numpy.floating` or :class:`numpy.ndarray`
Corresponding *luminance* :math:`L` of the image.
Notes
-----
+------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``V`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
+------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``L`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
References
----------
:cite:`InternationalTelecommunicationUnion2015i`
Examples
--------
>>> oetf_inverse_BT709(0.409007728864150) # doctest: +ELLIPSIS
0.1...
"""
return oetf_inverse_BT601(V)