Source code for colour.models.rgb.transfer_functions.cineon

# -*- coding: utf-8 -*-
"""
Kodak Cineon Encoding
=====================

Defines the *Kodak Cineon* encoding:

-   :func:`colour.models.log_encoding_Cineon`
-   :func:`colour.models.log_decoding_Cineon`

See Also
--------
`RGB Colourspaces Jupyter Notebook
<http://nbviewer.jupyter.org/github/colour-science/colour-notebooks/\
blob/master/notebooks/models/rgb.ipynb>`_

References
----------
-   :cite:`SonyImageworks2012a` : Sony Imageworks. (2012). make.py. Retrieved
    November 27, 2014, from https://github.com/imageworks/OpenColorIO-Configs/\
blob/master/nuke-default/make.py
"""

from __future__ import division, unicode_literals

import numpy as np

__author__ = 'Colour Developers'
__copyright__ = 'Copyright (C) 2013-2018 - 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_Cineon', 'log_decoding_Cineon']


[docs]def log_encoding_Cineon(x, black_offset=10 ** ((95 - 685) / 300)): """ Defines the *Cineon* log encoding curve / opto-electronic transfer function. Parameters ---------- x : numeric or array_like Linear data :math:`x`. black_offset : numeric or array_like Black offset. Returns ------- numeric or ndarray Non-linear data :math:`y`. References ---------- - :cite:`SonyImageworks2012a` Examples -------- >>> log_encoding_Cineon(0.18) # doctest: +ELLIPSIS 0.4573196... """ x = np.asarray(x) return (( 685 + 300 * np.log10(x * (1 - black_offset) + black_offset)) / 1023)
[docs]def log_decoding_Cineon(y, black_offset=10 ** ((95 - 685) / 300)): """ Defines the *Cineon* log decoding curve / electro-optical transfer function. Parameters ---------- y : numeric or array_like Non-linear data :math:`y`. black_offset : numeric or array_like Black offset. Returns ------- numeric or ndarray Linear data :math:`x`. References ---------- - :cite:`SonyImageworks2012a` Examples -------- >>> log_decoding_Cineon(0.457319613085418) # doctest: +ELLIPSIS 0.1799999... """ y = np.asarray(y) return ((10 ** ((1023 * y - 685) / 300) - black_offset) / (1 - black_offset))