#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
GoPro Encodings
===============
Defines the *GoPro* encodings:
- :func:`log_encoding_Protune`
- :func:`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
----------
.. [1] 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
__author__ = 'Colour Developers'
__copyright__ = 'Copyright (C) 2013-2017 - Colour Developers'
__license__ = 'New BSD License - http://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`.
Examples
--------
>>> log_encoding_Protune(0.18) # doctest: +ELLIPSIS
0.6456234...
"""
x = np.asarray(x)
return np.log(x * 112 + 1) / np.log(113)
[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`.
Examples
--------
>>> log_decoding_Protune(0.645623486803636) # doctest: +ELLIPSIS
0.1...
"""
y = np.asarray(y)
return (113 ** y - 1) / 112