# -*- coding: utf-8 -*-
"""
ITU-R BT.709-6
==============
Defines *ITU-R BT.709-6* opto-electrical transfer function (OETF / OECF) and
its inverse:
- :func:`colour.models.oetf_BT709`
- :func:`colour.models.oetf_inverse_BT709`
See Also
--------
`RGB Colourspaces Jupyter Notebook
<http://nbviewer.jupyter.org/github/colour-science/colour-notebooks/\
blob/master/notebooks/models/rgb.ipynb>`_
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. Retrieved from
https://www.itu.int/dms_pubrec/itu-r/rec/bt/\
R-REC-BT.709-6-201506-I!!PDF-E.pdf
"""
from __future__ import division, unicode_literals
from colour.models.rgb.transfer_functions import oetf_BT601, oetf_inverse_BT601
__author__ = 'Colour Developers'
__copyright__ = 'Copyright (C) 2013-2019 - Colour Developers'
__license__ = 'New BSD License - https://opensource.org/licenses/BSD-3-Clause'
__maintainer__ = 'Colour Developers'
__email__ = 'colour-science@googlegroups.com'
__status__ = 'Production'
__all__ = ['oetf_BT709', 'oetf_inverse_BT709']
[docs]def oetf_BT709(L):
"""
Defines *Recommendation ITU-R BT.709-6* opto-electronic transfer function
(OETF / OECF).
Parameters
----------
L : numeric or array_like
*Luminance* :math:`L` of the image.
Returns
-------
numeric or 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):
"""
Defines *Recommendation ITU-R BT.709-6* inverse opto-electronic transfer
function (OETF / OECF).
Parameters
----------
V : numeric or array_like
Electrical signal :math:`V`.
Returns
-------
numeric or 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)