# -*- coding: utf-8 -*-
"""
GoPro Encoding
==============
Defines the *GoPro* *Protune* encoding:
- :func:`colour.models.log_encoding_Protune`
- :func:`colour.models.log_decoding_Protune`
See Also
--------
`RGB Colourspaces Jupyter Notebook
<http://nbviewer.jupyter.org/github/colour-science/colour-notebooks/\
blob/master/notebooks/models/rgb.ipynb>`_
References
----------
- :cite:`GoPro2016a` : GoPro, Duiker, H.-P., & Mansencal, T. (2016).
gopro.py. Retrieved April 12, 2017, from
https://github.com/hpd/OpenColorIO-Configs/blob/master/aces_1.0.3/python/\
aces_ocio/colorspaces/gopro.py
"""
from __future__ import division, unicode_literals
import numpy as np
from colour.utilities import from_range_1, to_domain_1
__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__ = ['log_encoding_Protune', 'log_decoding_Protune']
[docs]def log_encoding_Protune(x):
"""
Defines the *Protune* log encoding curve / opto-electronic transfer
function.
Parameters
----------
x : numeric or array_like
Linear data :math:`x`.
Returns
-------
numeric or ndarray
Non-linear data :math:`y`.
Notes
-----
+------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``x`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
+------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``y`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
References
----------
:cite:`GoPro2016a`
Examples
--------
>>> log_encoding_Protune(0.18) # doctest: +ELLIPSIS
0.6456234...
"""
x = to_domain_1(x)
y = np.log(x * 112 + 1) / np.log(113)
return from_range_1(y)
[docs]def log_decoding_Protune(y):
"""
Defines the *Protune* log decoding curve / electro-optical transfer
function.
Parameters
----------
y : numeric or array_like
Non-linear data :math:`y`.
Returns
-------
numeric or ndarray
Linear data :math:`x`.
Notes
-----
+------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``y`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
+------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``x`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
References
----------
:cite:`GoPro2016a`
Examples
--------
>>> log_decoding_Protune(0.645623486803636) # doctest: +ELLIPSIS
0.1...
"""
y = to_domain_1(y)
x = (113 ** y - 1) / 112
return from_range_1(x)