#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
ACES RGB Colourspace
====================
Defines the *ACES RGB* colourspace and its variations:
- :attr:`ACES_RGB_COLOURSPACE`
- :attr:`ACES_RGB_LOG_COLOURSPACE`
- :attr:`ACES_RGB_PROXY_10_COLOURSPACE`
- :attr:`ACES_RGB_PROXY_12_COLOURSPACE`
See Also
--------
`RGB Colourspaces IPython Notebook
<http://nbviewer.ipython.org/github/colour-science/colour-ipython/blob/master/notebooks/models/rgb.ipynb>`_ # noqa
References
----------
.. [1] http://www.oscars.org/science-technology/council/projects/aces.html
(Last accessed 24 February 2014)
.. [2] `Academy Color Encoding Specification (ACES)
<https://www.dropbox.com/sh/nt9z9m6utzvkc5m/AACBum5OdkLPCZ3d6trfVeU8a/ACES_v1.0.1.pdf>`_ # noqa
(Last accessed 24 February 2014)
"""
from __future__ import division, unicode_literals
import math
import numpy as np
from colour.colorimetry import ILLUMINANTS
from colour.utilities import Structure
from colour.models import RGB_Colourspace
from colour.utilities import CaseInsensitiveMapping
__author__ = 'Colour Developers'
__copyright__ = 'Copyright (C) 2013 - 2014 - Colour Developers'
__license__ = 'New BSD License - http://opensource.org/licenses/BSD-3-Clause'
__maintainer__ = 'Colour Developers'
__email__ = 'colour-science@googlegroups.com'
__status__ = 'Production'
__all__ = ['ACES_RGB_PRIMARIES',
'ACES_RGB_WHITEPOINT',
'ACES_RGB_TO_XYZ_MATRIX',
'XYZ_TO_ACES_RGB_MATRIX',
'ACES_RGB_TRANSFER_FUNCTION',
'ACES_RGB_INVERSE_TRANSFER_FUNCTION',
'ACES_RGB_COLOURSPACE',
'ACES_RGB_LOG_CONSTANTS',
'ACES_RGB_LOG_TRANSFER_FUNCTION',
'ACES_RGB_LOG_INVERSE_TRANSFER_FUNCTION',
'ACES_RGB_LOG_COLOURSPACE',
'ACES_RGB_PROXY_10_CONSTANTS',
'ACES_RGB_PROXY_12_CONSTANTS',
'ACES_RGB_PROXY_CONSTANTS',
'ACES_RGB_PROXY_10_TRANSFER_FUNCTION',
'ACES_RGB_PROXY_10_INVERSE_TRANSFER_FUNCTION',
'ACES_RGB_PROXY_12_TRANSFER_FUNCTION',
'ACES_RGB_PROXY_12_INVERSE_TRANSFER_FUNCTION',
'ACES_RGB_PROXY_10_COLOURSPACE',
'ACES_RGB_PROXY_12_COLOURSPACE']
ACES_RGB_PRIMARIES = np.array(
[[0.73470, 0.26530],
[0.00000, 1.00000],
[0.00010, -0.07700]])
"""
*ACES RGB* colourspace primaries.
ACES_RGB_PRIMARIES : ndarray, (3, 2)
References
----------
.. [3] `Academy Color Encoding Specification (ACES)
<https://www.dropbox.com/sh/nt9z9m6utzvkc5m/AACBum5OdkLPCZ3d6trfVeU8a/ACES_v1.0.1.pdf>`_ # noqa
4.1.2 Color space chromaticities (Last accessed 24 February 2014)
"""
ACES_RGB_WHITEPOINT = ILLUMINANTS.get(
'CIE 1931 2 Degree Standard Observer').get('D60')
"""
*ACES RGB* colourspace whitepoint.
ACES_RGB_WHITEPOINT : tuple
"""
ACES_RGB_TO_XYZ_MATRIX = np.array(
[[9.52552396e-01, 0.00000000e+00, 9.36786317e-05],
[3.43966450e-01, 7.28166097e-01, -7.21325464e-02],
[0.00000000e+00, 0.00000000e+00, 1.00882518e+00]])
"""
*ACES RGB* colourspace to *CIE XYZ* colourspace matrix.
ACES_RGB_TO_XYZ_MATRIX : array_like, (3, 3)
References
----------
.. [4] http://www.dropbox.com/sh/iwd09buudm3lfod/gyjDF-k7oC/ACES_v1.0.1.pdf:
4.1.4 Converting ACES RGB values to CIE XYZ values
(Last accessed 24 February 2014)
"""
XYZ_TO_ACES_RGB_MATRIX = np.linalg.inv(ACES_RGB_TO_XYZ_MATRIX)
"""
*CIE XYZ* colourspace to *ACES RGB* colourspace matrix.
XYZ_TO_ACES_RGB_MATRIX : array_like, (3, 3)
"""
ACES_RGB_TRANSFER_FUNCTION = lambda x: x
"""
Transfer function from linear to *ACES RGB* colourspace.
ACES_RGB_TRANSFER_FUNCTION : object
"""
ACES_RGB_INVERSE_TRANSFER_FUNCTION = lambda x: x
"""
Inverse transfer function from *ACES RGB* colourspace to linear.
ACES_RGB_INVERSE_TRANSFER_FUNCTION : object
"""
ACES_RGB_COLOURSPACE = RGB_Colourspace(
'ACES RGB',
ACES_RGB_PRIMARIES,
ACES_RGB_WHITEPOINT,
ACES_RGB_TO_XYZ_MATRIX,
XYZ_TO_ACES_RGB_MATRIX,
ACES_RGB_TRANSFER_FUNCTION,
ACES_RGB_INVERSE_TRANSFER_FUNCTION)
"""
*ACES RGB* colourspace.
ACES_RGB_COLOURSPACE : RGB_Colourspace
"""
ACES_RGB_LOG_CONSTANTS = Structure(
log_unity=32768,
log_xperstop=2048,
denorm_trans=math.pow(2, -15),
denorm_fake0=math.pow(2, -16))
"""
*ACES RGB Log* colourspace constants.
ACES_RGB_LOG_CONSTANTS : Structure
"""
def _aces_rgb_log_transfer_function(value, is_16_bit_integer=False):
"""
Defines the *ACES RGB Log* colourspace transfer function.
Parameters
----------
value : numeric
value.
is_16_bit_integer : bool
Is value 16 bit integer.
Returns
-------
numeric
Companded value.
"""
if value < 0:
return 0
if value < ACES_RGB_LOG_CONSTANTS.denorm_trans:
value = ACES_RGB_LOG_CONSTANTS.denorm_fake0 + (value / 2)
value = ((math.log10(value) / math.log10(2)) *
ACES_RGB_LOG_CONSTANTS.log_xperstop +
ACES_RGB_LOG_CONSTANTS.log_unity)
if is_16_bit_integer:
value = min(math.floor(value) + 0.5, 65535)
return value
def _aces_rgb_log_inverse_transfer_function(value):
"""
Defines the *ACES RGB Log* colourspace inverse transfer function.
Parameters
----------
value : numeric
value.
Returns
-------
numeric
Companded value.
"""
value = (math.pow(2,
(value - ACES_RGB_LOG_CONSTANTS.log_unity) /
ACES_RGB_LOG_CONSTANTS.log_xperstop))
if value < ACES_RGB_LOG_CONSTANTS.denorm_trans:
value = (value - ACES_RGB_LOG_CONSTANTS.denorm_fake0) * 2
return value
ACES_RGB_LOG_TRANSFER_FUNCTION = _aces_rgb_log_transfer_function
"""
Transfer function from linear to *ACES RGB Log* colourspace.
ACES_RGB_LOG_TRANSFER_FUNCTION : object
"""
ACES_RGB_LOG_INVERSE_TRANSFER_FUNCTION = (
_aces_rgb_log_inverse_transfer_function)
"""
Inverse transfer function from *ACES RGB Log* colourspace to linear.
ACES_RGB_LOG_INVERSE_TRANSFER_FUNCTION : object
"""
ACES_RGB_LOG_COLOURSPACE = RGB_Colourspace(
'ACES RGB Log',
ACES_RGB_PRIMARIES,
ACES_RGB_WHITEPOINT,
ACES_RGB_TO_XYZ_MATRIX,
XYZ_TO_ACES_RGB_MATRIX,
ACES_RGB_LOG_TRANSFER_FUNCTION,
ACES_RGB_LOG_INVERSE_TRANSFER_FUNCTION)
"""
*ACES RGB Log* colourspace.
ACES_RGB_LOG_COLOURSPACE : RGB_Colourspace
References
----------
.. [5] `Logarithmic Encoding of ACES Data for use within Color Grading Systems
<http://www.dropbox.com/sh/iwd09buudm3lfod/AAA-X1nVs_XLjWlzNhfhqiIna/ACESlog_v1.0.pdf>`_ # noqa
(Last accessed 17 May 2014)
"""
ACES_RGB_PROXY_10_CONSTANTS = Structure(
CV_min=0,
CV_max=1023,
steps_per_stop=50,
mid_CV_offset=425,
mid_log_offset=-2.5)
"""
*ACES RGB Proxy 10* colourspace constants.
ACES_RGB_PROXY_10_CONSTANTS : Structure
"""
ACES_RGB_PROXY_12_CONSTANTS = Structure(
CV_min=0,
CV_max=4095,
steps_per_stop=200,
mid_CV_offset=1700,
mid_log_offset=-2.5)
"""
*ACES RGB Proxy 12* colourspace constants.
ACES_RGB_PROXY_12_CONSTANTS : Structure
"""
ACES_RGB_PROXY_CONSTANTS = CaseInsensitiveMapping(
{'10 Bit': ACES_RGB_PROXY_10_CONSTANTS,
'12 Bit': ACES_RGB_PROXY_12_CONSTANTS})
"""
Aggregated *ACES RGB Proxy* colourspace constants.
ACES_RGB_PROXY_CONSTANTS : dict
('10 Bit', '12 Bit')
"""
def _aces_rgb_proxy_transfer_function(value, bit_depth='10 Bit'):
"""
Defines the *ACES RGB Proxy* colourspace transfer function.
Parameters
----------
value : numeric
value.
bit_depth : unicode ('10 Bit', '12 Bit')
*ACES RGB Proxy* bit depth.
Returns
-------
numeric
Companded value.
"""
constants = ACES_RGB_PROXY_CONSTANTS.get(bit_depth)
if value > 0:
return max(constants.CV_min,
min(constants.CV_max,
((math.log10(value) / (math.log10(2)) -
constants.mid_log_offset) * constants.steps_per_stop +
constants.mid_CV_offset)) + 0.5)
else:
return constants.CV_min
def _aces_rgb_proxy_inverse_transfer_function(value, bit_depth='10 Bit'):
"""
Defines the *ACES RGB Proxy* colourspace inverse transfer function.
Parameters
----------
value : numeric
value.
bit_depth : str ('10 Bit', '12 Bit')
*ACES RGB Proxy* bit depth.
Returns
-------
numeric
Companded value.
"""
constants = ACES_RGB_PROXY_CONSTANTS.get(bit_depth)
return math.pow(2,
((((value - constants.mid_CV_offset) /
constants.steps_per_stop) + constants.mid_log_offset)))
ACES_RGB_PROXY_10_TRANSFER_FUNCTION = lambda x: (
_aces_rgb_proxy_transfer_function(x))
"""
Transfer function from linear to *ACES RGB Proxy 10* colourspace.
ACES_RGB_PROXY_10_TRANSFER_FUNCTION : object
"""
ACES_RGB_PROXY_10_INVERSE_TRANSFER_FUNCTION = lambda x: (
_aces_rgb_proxy_inverse_transfer_function(x))
"""
Inverse transfer function from *ACES RGB Proxy 10* colourspace to linear.
ACES_RGB_PROXY_10_INVERSE_TRANSFER_FUNCTION : object
"""
ACES_RGB_PROXY_12_TRANSFER_FUNCTION = lambda x: (
_aces_rgb_proxy_transfer_function(x, bit_depth='12 Bit'))
"""
Transfer function from linear to *ACES RGB Proxy 12* colourspace.
ACES_RGB_PROXY_12_TRANSFER_FUNCTION : object
"""
ACES_RGB_PROXY_12_INVERSE_TRANSFER_FUNCTION = lambda x: (
_aces_rgb_proxy_inverse_transfer_function(x, bit_depth='12 Bit'))
"""
Inverse transfer function from *ACES RGB Proxy 12* colourspace to linear.
ACES_RGB_PROXY_12_INVERSE_TRANSFER_FUNCTION : object
"""
ACES_RGB_PROXY_10_COLOURSPACE = RGB_Colourspace(
'ACES RGB Proxy 10',
ACES_RGB_PRIMARIES,
ACES_RGB_WHITEPOINT,
ACES_RGB_TO_XYZ_MATRIX,
XYZ_TO_ACES_RGB_MATRIX,
ACES_RGB_PROXY_10_TRANSFER_FUNCTION,
ACES_RGB_PROXY_10_INVERSE_TRANSFER_FUNCTION)
"""
*ACES RGB Proxy 10* colourspace.
ACES_RGB_PROXY_10_COLOURSPACE : RGB_Colourspace
References
----------
.. [6] `ACESproxy, an Integer Log Encoding of ACES Image Data
<http://www.dropbox.com/sh/iwd09buudm3lfod/AAAsl8WskbNNAJXh1r0dPlp2a/ACESproxy_v1.1.pdf>`_ # noqa
(Last accessed 17 May 2014)
"""
ACES_RGB_PROXY_12_COLOURSPACE = RGB_Colourspace(
'ACES RGB Proxy 12',
ACES_RGB_PRIMARIES,
ACES_RGB_WHITEPOINT,
ACES_RGB_TO_XYZ_MATRIX,
XYZ_TO_ACES_RGB_MATRIX,
ACES_RGB_PROXY_12_TRANSFER_FUNCTION,
ACES_RGB_PROXY_12_INVERSE_TRANSFER_FUNCTION)
"""
*ACES RGB Proxy 12* colourspace.
ACES_RGB_PROXY_12_COLOURSPACE : RGB_Colourspace
References
----------
.. [7] `ACESproxy, an Integer Log Encoding of ACES Image Data
<http://www.dropbox.com/sh/iwd09buudm3lfod/AAAsl8WskbNNAJXh1r0dPlp2a/ACESproxy_v1.1.pdf>`_ # noqa
(Last accessed 17 May 2014)
"""
Colour 0.3