# -*- coding: utf-8 -*-
"""
Academy Color Encoding System - Log Encodings
=============================================
Defines the *Academy Color Encoding System* (ACES) log encodings:
- :func:`colour.models.log_encoding_ACESproxy`
- :func:`colour.models.log_decoding_ACESproxy`
- :func:`colour.models.log_encoding_ACEScc`
- :func:`colour.models.log_decoding_ACEScc`
- :func:`colour.models.log_encoding_ACEScct`
- :func:`colour.models.log_decoding_ACEScct`
See Also
--------
`RGB Colourspaces Jupyter Notebook
<http://nbviewer.jupyter.org/github/colour-science/colour-notebooks/\
blob/master/notebooks/models/rgb.ipynb>`_
References
----------
- :cite:`TheAcademyofMotionPictureArtsandSciences2014q` : The Academy of
Motion Picture Arts and Sciences, Science and Technology Council, & Academy
Color Encoding System (ACES) Project Subcommittee. (2014). Technical
Bulletin TB-2014-004 - Informative Notes on SMPTE ST 2065-1 - Academy Color
Encoding Specification (ACES). Retrieved from
https://github.com/ampas/aces-dev/tree/master/documents
- :cite:`TheAcademyofMotionPictureArtsandSciences2014r` : The Academy of
Motion Picture Arts and Sciences, Science and Technology Council, & Academy
Color Encoding System (ACES) Project Subcommittee. (2014). Technical
Bulletin TB-2014-012 - Academy Color Encoding System Version 1.0 Component
Names. Retrieved from
https://github.com/ampas/aces-dev/tree/master/documents
- :cite:`TheAcademyofMotionPictureArtsandSciences2014s` : The Academy of
Motion Picture Arts and Sciences, Science and Technology Council, & Academy
Color Encoding System (ACES) Project Subcommittee. (2014). Specification
S-2013-001 - ACESproxy, an Integer Log Encoding of ACES Image Data.
Retrieved from https://github.com/ampas/aces-dev/tree/master/documents
- :cite:`TheAcademyofMotionPictureArtsandSciences2014t` : The Academy of
Motion Picture Arts and Sciences, Science and Technology Council, & Academy
Color Encoding System (ACES) Project Subcommittee. (2014). Specification
S-2014-003 - ACEScc, A Logarithmic Encoding of ACES Data for use within
Color Grading Systems. Retrieved from
https://github.com/ampas/aces-dev/tree/master/documents
- :cite:`TheAcademyofMotionPictureArtsandSciences2016c` : The Academy of
Motion Picture Arts and Sciences, Science and Technology Council, & Academy
Color Encoding System (ACES) Project. (2016). Specification S-2016-001 -
ACEScct, A Quasi-Logarithmic Encoding of ACES Data for use within Color
Grading Systems. Retrieved October 10, 2016, from
https://github.com/ampas/aces-dev/tree/v1.0.3/documents
- :cite:`TheAcademyofMotionPictureArtsandSciencese` : The Academy of Motion
Picture Arts and Sciences, Science and Technology Council, & Academy Color
Encoding System (ACES) Project Subcommittee. (n.d.). Academy Color Encoding
System. Retrieved February 24, 2014, from
http://www.oscars.org/science-technology/council/projects/aces.html
"""
from __future__ import division, unicode_literals
import numpy as np
from colour.utilities import (Structure, as_float, as_int, 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__ = [
'ACES_PROXY_10_CONSTANTS', 'ACES_PROXY_12_CONSTANTS',
'ACES_PROXY_CONSTANTS', 'ACES_CCT_CONSTANTS', 'log_encoding_ACESproxy',
'log_decoding_ACESproxy', 'log_encoding_ACEScc', 'log_decoding_ACEScc',
'log_encoding_ACEScct', 'log_decoding_ACEScct'
]
ACES_PROXY_10_CONSTANTS = Structure(
CV_min=64,
CV_max=940,
steps_per_stop=50,
mid_CV_offset=425,
mid_log_offset=2.5)
"""
*ACESproxy* 10 bit colourspace constants.
ACES_PROXY_10_CONSTANTS : Structure
"""
ACES_PROXY_12_CONSTANTS = Structure(
CV_min=256,
CV_max=3760,
steps_per_stop=200,
mid_CV_offset=1700,
mid_log_offset=2.5)
"""
*ACESproxy* 12 bit colourspace constants.
ACES_PROXY_12_CONSTANTS : Structure
"""
ACES_PROXY_CONSTANTS = {
10: ACES_PROXY_10_CONSTANTS,
12: ACES_PROXY_12_CONSTANTS
}
"""
Aggregated *ACESproxy* colourspace constants.
ACES_PROXY_CONSTANTS : dict
**{10, 12}**
"""
ACES_CCT_CONSTANTS = Structure(
X_BRK=0.0078125,
Y_BRK=0.155251141552511,
A=10.5402377416545,
B=0.0729055341958355)
"""
*ACEScct* colourspace constants.
ACES_CCT_CONSTANTS : Structure
"""
# pylint: disable=W0102
[docs]def log_encoding_ACESproxy(lin_AP1,
bit_depth=10,
out_int=False,
constants=ACES_PROXY_CONSTANTS):
"""
Defines the *ACESproxy* colourspace log encoding curve / opto-electronic
transfer function.
Parameters
----------
lin_AP1 : numeric or array_like
*lin_AP1* value.
bit_depth : int, optional
**{10, 12}**,
*ACESproxy* bit depth.
out_int : bool, optional
Whether to return value as integer code value or float equivalent of a
code value at a given bit depth.
constants : Structure, optional
*ACESproxy* constants.
Returns
-------
numeric or ndarray
*ACESproxy* non-linear value.
Notes
-----
+----------------+-----------------------+---------------+
| **Domain \\*** | **Scale - Reference** | **Scale - 1** |
+================+=======================+===============+
| ``lin_AP1`` | [0, 1] | [0, 1] |
+----------------+-----------------------+---------------+
+----------------+-----------------------+---------------+
| **Range \\*** | **Scale - Reference** | **Scale - 1** |
+================+=======================+===============+
| ``ACESproxy`` | [0, 1] | [0, 1] |
+----------------+-----------------------+---------------+
- \\* This definition has an output integer switch, thus the domain-range
scale information is only given for the floating point mode.
References
----------
:cite:`TheAcademyofMotionPictureArtsandSciences2014q`,
:cite:`TheAcademyofMotionPictureArtsandSciences2014r`,
:cite:`TheAcademyofMotionPictureArtsandSciences2014s`,
:cite:`TheAcademyofMotionPictureArtsandSciencese`
Examples
--------
>>> log_encoding_ACESproxy(0.18) # doctest: +ELLIPSIS
0.4164222...
>>> log_encoding_ACESproxy(0.18, out_int=True)
426
"""
lin_AP1 = to_domain_1(lin_AP1)
constants = constants[bit_depth]
CV_min = np.resize(constants.CV_min, lin_AP1.shape)
CV_max = np.resize(constants.CV_max, lin_AP1.shape)
def float_2_cv(x):
"""
Converts given numeric to code value.
"""
return np.maximum(CV_min, np.minimum(CV_max, np.round(x)))
ACESproxy = np.where(
lin_AP1 > 2 ** -9.72,
float_2_cv((np.log2(lin_AP1) + constants.mid_log_offset) *
constants.steps_per_stop + constants.mid_CV_offset),
np.resize(CV_min, lin_AP1.shape),
)
if out_int:
return as_int(np.round(ACESproxy))
else:
return as_float(from_range_1(ACESproxy / (2 ** bit_depth - 1)))
# pylint: disable=W0102
[docs]def log_decoding_ACESproxy(ACESproxy,
bit_depth=10,
in_int=False,
constants=ACES_PROXY_CONSTANTS):
"""
Defines the *ACESproxy* colourspace log decoding curve / electro-optical
transfer function.
Parameters
----------
ACESproxy : numeric or array_like
*ACESproxy* non-linear value.
bit_depth : int, optional
**{10, 12}**,
*ACESproxy* bit depth.
in_int : bool, optional
Whether to treat the input value as integer code value or float
equivalent of a code value at a given bit depth.
constants : Structure, optional
*ACESproxy* constants.
Returns
-------
numeric or ndarray
*lin_AP1* value.
Notes
-----
+----------------+-----------------------+---------------+
| **Domain \\*** | **Scale - Reference** | **Scale - 1** |
+================+=======================+===============+
| ``ACESproxy`` | [0, 1] | [0, 1] |
+----------------+-----------------------+---------------+
+----------------+-----------------------+---------------+
| **Range \\*** | **Scale - Reference** | **Scale - 1** |
+================+=======================+===============+
| ``lin_AP1`` | [0, 1] | [0, 1] |
+----------------+-----------------------+---------------+
- \\* This definition has an input integer switch, thus the domain-range
scale information is only given for the floating point mode.
References
----------
:cite:`TheAcademyofMotionPictureArtsandSciences2014q`,
:cite:`TheAcademyofMotionPictureArtsandSciences2014r`,
:cite:`TheAcademyofMotionPictureArtsandSciences2014s`,
:cite:`TheAcademyofMotionPictureArtsandSciencese`
Examples
--------
>>> log_decoding_ACESproxy(0.416422287390029) # doctest: +ELLIPSIS
0.1...
>>> log_decoding_ACESproxy(426, in_int=True) # doctest: +ELLIPSIS
0.1...
"""
ACESproxy = to_domain_1(ACESproxy)
constants = constants[bit_depth]
if not in_int:
ACESproxy = ACESproxy * (2 ** bit_depth - 1)
lin_AP1 = (
2 ** (((ACESproxy - constants.mid_CV_offset) / constants.steps_per_stop
- constants.mid_log_offset)))
return from_range_1(lin_AP1)
[docs]def log_encoding_ACEScc(lin_AP1):
"""
Defines the *ACEScc* colourspace log encoding / opto-electronic transfer
function.
Parameters
----------
lin_AP1 : numeric or array_like
*lin_AP1* value.
Returns
-------
numeric or ndarray
*ACEScc* non-linear value.
Notes
-----
+-------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+=============+=======================+===============+
| ``lin_AP1`` | [0, 1] | [0, 1] |
+-------------+-----------------------+---------------+
+-------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+=============+=======================+===============+
| ``ACEScc`` | [0, 1] | [0, 1] |
+-------------+-----------------------+---------------+
References
----------
:cite:`TheAcademyofMotionPictureArtsandSciences2014q`,
:cite:`TheAcademyofMotionPictureArtsandSciences2014r`,
:cite:`TheAcademyofMotionPictureArtsandSciences2014t`,
:cite:`TheAcademyofMotionPictureArtsandSciencese`
Examples
--------
>>> log_encoding_ACEScc(0.18) # doctest: +ELLIPSIS
0.4135884...
"""
lin_AP1 = to_domain_1(lin_AP1)
ACEScc = np.where(
lin_AP1 < 0,
(np.log2(2 ** -16) + 9.72) / 17.52,
(np.log2(2 ** -16 + lin_AP1 * 0.5) + 9.72) / 17.52,
)
ACEScc = np.where(
lin_AP1 >= 2 ** -15,
(np.log2(lin_AP1) + 9.72) / 17.52,
ACEScc,
)
return as_float(from_range_1(ACEScc))
[docs]def log_decoding_ACEScc(ACEScc):
"""
Defines the *ACEScc* colourspace log decoding / electro-optical transfer
function.
Parameters
----------
ACEScc : numeric or array_like
*ACEScc* non-linear value.
Returns
-------
numeric or ndarray
*lin_AP1* value.
Notes
-----
+-------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+=============+=======================+===============+
| ``ACEScc`` | [0, 1] | [0, 1] |
+-------------+-----------------------+---------------+
+-------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+=============+=======================+===============+
| ``lin_AP1`` | [0, 1] | [0, 1] |
+-------------+-----------------------+---------------+
References
----------
:cite:`TheAcademyofMotionPictureArtsandSciences2014q`,
:cite:`TheAcademyofMotionPictureArtsandSciences2014r`,
:cite:`TheAcademyofMotionPictureArtsandSciences2014t`,
:cite:`TheAcademyofMotionPictureArtsandSciencese`
Examples
--------
>>> log_decoding_ACEScc(0.413588402492442) # doctest: +ELLIPSIS
0.1799999...
"""
ACEScc = to_domain_1(ACEScc)
lin_AP1 = np.where(
ACEScc < (9.72 - 15) / 17.52,
(2 ** (ACEScc * 17.52 - 9.72) - 2 ** -16) * 2,
2 ** (ACEScc * 17.52 - 9.72),
)
lin_AP1 = np.where(
ACEScc >= (np.log2(65504) + 9.72) / 17.52,
65504,
lin_AP1,
)
return as_float(from_range_1(lin_AP1))
# pylint: disable=W0102
[docs]def log_encoding_ACEScct(lin_AP1, constants=ACES_CCT_CONSTANTS):
"""
Defines the *ACEScct* colourspace log encoding / opto-electronic transfer
function.
Parameters
----------
lin_AP1 : numeric or array_like
*lin_AP1* value.
constants : Structure, optional
*ACEScct* constants.
Returns
-------
numeric or ndarray
*ACEScct* non-linear value.
Notes
-----
+-------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+=============+=======================+===============+
| ``lin_AP1`` | [0, 1] | [0, 1] |
+-------------+-----------------------+---------------+
+-------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+=============+=======================+===============+
| ``ACEScct`` | [0, 1] | [0, 1] |
+-------------+-----------------------+---------------+
References
----------
:cite:`TheAcademyofMotionPictureArtsandSciences2014q`,
:cite:`TheAcademyofMotionPictureArtsandSciences2014r`,
:cite:`TheAcademyofMotionPictureArtsandSciences2016c`,
:cite:`TheAcademyofMotionPictureArtsandSciencese`
Examples
--------
>>> log_encoding_ACEScct(0.18) # doctest: +ELLIPSIS
0.4135884...
"""
lin_AP1 = to_domain_1(lin_AP1)
ACEScct = np.where(
lin_AP1 <= constants.X_BRK,
constants.A * lin_AP1 + constants.B,
(np.log2(lin_AP1) + 9.72) / 17.52,
)
return as_float(from_range_1(ACEScct))
# pylint: disable=W0102
[docs]def log_decoding_ACEScct(ACEScct, constants=ACES_CCT_CONSTANTS):
"""
Defines the *ACEScct* colourspace log decoding / electro-optical transfer
function.
Parameters
----------
ACEScct : numeric or array_like
*ACEScct* non-linear value.
constants : Structure, optional
*ACEScct* constants.
Returns
-------
numeric or ndarray
*lin_AP1* value.
References
----------
:cite:`TheAcademyofMotionPictureArtsandSciences2014q`,
:cite:`TheAcademyofMotionPictureArtsandSciences2014r`,
:cite:`TheAcademyofMotionPictureArtsandSciences2016c`,
:cite:`TheAcademyofMotionPictureArtsandSciencese`
Notes
-----
+-------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+=============+=======================+===============+
| ``ACEScct`` | [0, 1] | [0, 1] |
+-------------+-----------------------+---------------+
+-------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+=============+=======================+===============+
| ``lin_AP1`` | [0, 1] | [0, 1] |
+-------------+-----------------------+---------------+
Examples
--------
>>> log_decoding_ACEScct(0.413588402492442) # doctest: +ELLIPSIS
0.1799999...
"""
ACEScct = to_domain_1(ACEScct)
lin_AP1 = np.where(
ACEScct > constants.Y_BRK,
2 ** (ACEScct * 17.52 - 9.72),
(ACEScct - constants.B) / constants.A,
)
return as_float(from_range_1(lin_AP1))