# -*- coding: utf-8 -*-
"""
Canon Log Encodings
===================
Defines the *Canon Log* encodings:
- :func:`colour.models.log_encoding_CanonLog`
- :func:`colour.models.log_decoding_CanonLog`
- :func:`colour.models.log_encoding_CanonLog2`
- :func:`colour.models.log_decoding_CanonLog2`
- :func:`colour.models.log_encoding_CanonLog3`
- :func:`colour.models.log_decoding_CanonLog3`
See Also
--------
`RGB Colourspaces Jupyter Notebook
<http://nbviewer.jupyter.org/github/colour-science/colour-notebooks/\
blob/master/notebooks/models/rgb.ipynb>`_
Notes
-----
- :cite:`Canona` is available as a *Drivers & Downloads* *Software* for
Windows 10 (x64) *Operating System*, a copy of the archive is hosted at
this url: https://drive.google.com/open?id=0B_IQZQdc4Vy8ZGYyY29pMEVwZU0
References
----------
- :cite:`Canona` : Canon. (n.d.). EOS C300 Mark II - EOS C300 Mark II Input
Transform Version 2.0 (for Cinema Gamut / BT.2020). Retrieved August 23,
2016, from https://www.usa.canon.com/internet/portal/us/home/support/\
details/cameras/cinema-eos/eos-c300-mark-ii
- :cite:`Thorpe2012a` : Thorpe, L. (2012). CANON-LOG TRANSFER CHARACTERISTIC.
Retrieved from http://downloads.canon.com/CDLC/\
Canon-Log_Transfer_Characteristic_6-20-2012.pdf
"""
from __future__ import division, unicode_literals
import numpy as np
from colour.models.rgb.transfer_functions import full_to_legal, legal_to_full
from colour.utilities import (as_float, domain_range_scale, from_range_1,
to_domain_1)
from colour.utilities.deprecation import handle_arguments_deprecation
__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_CanonLog', 'log_decoding_CanonLog', 'log_encoding_CanonLog2',
'log_decoding_CanonLog2', 'log_encoding_CanonLog3',
'log_decoding_CanonLog3'
]
[docs]def log_encoding_CanonLog(x,
bit_depth=10,
out_normalised_code_value=True,
in_reflection=True,
**kwargs):
"""
Defines the *Canon Log* log encoding curve / opto-electronic transfer
function.
Parameters
----------
x : numeric or array_like
Linear data :math:`x`.
bit_depth : int, optional
Bit depth used for conversion.
out_normalised_code_value : bool, optional
Whether the *Canon Log* non-linear data is encoded as normalised code
values.
in_reflection : bool, optional
Whether the light level :math:`x` to a camera is reflection.
Other Parameters
----------------
\\**kwargs : dict, optional
Keywords arguments for deprecation management.
Returns
-------
numeric or ndarray
*Canon Log* non-linear data.
References
----------
:cite:`Thorpe2012a`
Notes
-----
+------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``x`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
+------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``clog`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
Examples
--------
>>> log_encoding_CanonLog(0.18) * 100 # doctest: +ELLIPSIS
34.3389651...
The values of *Table 2 Canon-Log Code Values* table in :cite:`Thorpe2012a`
are obtained as follows:
>>> x = np.array([0, 2, 18, 90, 720]) / 100
>>> np.around(log_encoding_CanonLog(x) * (2 ** 10 - 1)).astype(np.int)
array([ 128, 169, 351, 614, 1016])
>>> np.around(log_encoding_CanonLog(x, 10, False) * 100, 1)
array([ 7.3, 12. , 32.8, 62.7, 108.7])
"""
out_normalised_code_value = handle_arguments_deprecation({
'ArgumentRenamed': [['out_legal', 'out_normalised_code_value']],
}, **kwargs).get('out_normalised_code_value', out_normalised_code_value)
x = to_domain_1(x)
if in_reflection:
x = x / 0.9
with domain_range_scale('ignore'):
clog = np.where(
x < log_decoding_CanonLog(0.0730597, bit_depth, False),
-(0.529136 * (np.log10(-x * 10.1596 + 1)) - 0.0730597),
0.529136 * np.log10(10.1596 * x + 1) + 0.0730597,
)
clog = (full_to_legal(clog, bit_depth)
if out_normalised_code_value else clog)
return as_float(from_range_1(clog))
[docs]def log_decoding_CanonLog(clog,
bit_depth=10,
in_normalised_code_value=True,
out_reflection=True,
**kwargs):
"""
Defines the *Canon Log* log decoding curve / electro-optical transfer
function.
Parameters
----------
clog : numeric or array_like
*Canon Log* non-linear data.
bit_depth : int, optional
Bit depth used for conversion.
in_normalised_code_value : bool, optional
Whether the *Canon Log* non-linear data is encoded with normalised
code values.
out_reflection : bool, optional
Whether the light level :math:`x` to a camera is reflection.
Other Parameters
----------------
\\**kwargs : dict, optional
Keywords arguments for deprecation management.
Returns
-------
numeric or ndarray
Linear data :math:`x`.
Notes
-----
+------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``clog`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
+------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``x`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
References
----------
:cite:`Thorpe2012a`
Examples
--------
>>> log_decoding_CanonLog(34.338965172606912 / 100) # doctest: +ELLIPSIS
0.17999999...
"""
in_normalised_code_value = handle_arguments_deprecation({
'ArgumentRenamed': [['in_legal', 'in_normalised_code_value']],
}, **kwargs).get('in_normalised_code_value', in_normalised_code_value)
clog = to_domain_1(clog)
clog = (legal_to_full(clog, bit_depth)
if in_normalised_code_value else clog)
x = np.where(
clog < 0.0730597,
-(10 ** ((0.0730597 - clog) / 0.529136) - 1) / 10.1596,
(10 ** ((clog - 0.0730597) / 0.529136) - 1) / 10.1596,
)
if out_reflection:
x = x * 0.9
return as_float(from_range_1(x))
[docs]def log_encoding_CanonLog2(x,
bit_depth=10,
out_normalised_code_value=True,
in_reflection=True,
**kwargs):
"""
Defines the *Canon Log 2* log encoding curve / opto-electronic transfer
function.
Parameters
----------
x : numeric or array_like
Linear data :math:`x`.
bit_depth : int, optional
Bit depth used for conversion.
out_normalised_code_value : bool, optional
Whether the *Canon Log 2* non-linear data is encoded as normalised
code values.
in_reflection : bool, optional
Whether the light level :math:`x` to a camera is reflection.
Other Parameters
----------------
\\**kwargs : dict, optional
Keywords arguments for deprecation management.
Returns
-------
numeric or ndarray
*Canon Log 2* non-linear data.
Notes
-----
+------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``x`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
+------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``clog2`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
References
----------
:cite:`Canona`
Examples
--------
>>> log_encoding_CanonLog2(0.18) * 100 # doctest: +ELLIPSIS
39.8254694...
"""
out_normalised_code_value = handle_arguments_deprecation({
'ArgumentRenamed': [['out_legal', 'out_normalised_code_value']],
}, **kwargs).get('out_normalised_code_value', out_normalised_code_value)
x = to_domain_1(x)
if in_reflection:
x = x / 0.9
with domain_range_scale('ignore'):
clog2 = np.where(
x < log_decoding_CanonLog2(0.035388128, bit_depth, False),
-(0.281863093 * (np.log10(-x * 87.09937546 + 1)) - 0.035388128),
0.281863093 * np.log10(x * 87.09937546 + 1) + 0.035388128,
)
clog2 = (full_to_legal(clog2, bit_depth)
if out_normalised_code_value else clog2)
return as_float(from_range_1(clog2))
[docs]def log_decoding_CanonLog2(clog2,
bit_depth=10,
in_normalised_code_value=True,
out_reflection=True,
**kwargs):
"""
Defines the *Canon Log 2* log decoding curve / electro-optical transfer
function.
Parameters
----------
clog2 : numeric or array_like
*Canon Log 2* non-linear data.
bit_depth : int, optional
Bit depth used for conversion.
in_normalised_code_value : bool, optional
Whether the *Canon Log 2* non-linear data is encoded with normalised
code values.
out_reflection : bool, optional
Whether the light level :math:`x` to a camera is reflection.
Other Parameters
----------------
\\**kwargs : dict, optional
Keywords arguments for deprecation management.
Returns
-------
numeric or ndarray
Linear data :math:`x`.
Notes
-----
+------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``clog2`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
+------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``x`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
References
----------
:cite:`Canona`
Examples
--------
>>> log_decoding_CanonLog2(39.825469498316735 / 100) # doctest: +ELLIPSIS
0.1799999...
"""
in_normalised_code_value = handle_arguments_deprecation({
'ArgumentRenamed': [['in_legal', 'in_normalised_code_value']],
}, **kwargs).get('in_normalised_code_value', in_normalised_code_value)
clog2 = to_domain_1(clog2)
clog2 = (legal_to_full(clog2, bit_depth)
if in_normalised_code_value else clog2)
x = np.where(
clog2 < 0.035388128,
-(10 ** ((0.035388128 - clog2) / 0.281863093) - 1) / 87.09937546,
(10 ** ((clog2 - 0.035388128) / 0.281863093) - 1) / 87.09937546,
)
if out_reflection:
x = x * 0.9
return as_float(from_range_1(x))
[docs]def log_encoding_CanonLog3(x,
bit_depth=10,
out_normalised_code_value=True,
in_reflection=True,
**kwargs):
"""
Defines the *Canon Log 3* log encoding curve / opto-electronic transfer
function.
Parameters
----------
x : numeric or array_like
Linear data :math:`x`.
bit_depth : int, optional
Bit depth used for conversion.
out_normalised_code_value : bool, optional
Whether the *Canon Log 3* non-linear data is encoded as normalised code
values.
in_reflection : bool, optional
Whether the light level :math:`x` to a camera is reflection.
Other Parameters
----------------
\\**kwargs : dict, optional
Keywords arguments for deprecation management.
Returns
-------
numeric or ndarray
*Canon Log 3* non-linear data.
Notes
-----
- Introspection of the grafting points by Shaw, N. (2018) shows that the
*Canon Log 3* IDT was likely derived from its encoding curve as the
later is grafted at *+/-0.014*::
>>> clog3 = 0.04076162
>>> (clog3 - 0.073059361) / 2.3069815
-0.014000000000000002
>>> clog3 = 0.105357102
>>> (clog3 - 0.073059361) / 2.3069815
0.013999999999999997
Notes
-----
+------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``x`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
+------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``clog3`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
References
----------
:cite:`Canona`
Examples
--------
>>> log_encoding_CanonLog3(0.18) * 100 # doctest: +ELLIPSIS
34.3389369...
"""
out_normalised_code_value = handle_arguments_deprecation({
'ArgumentRenamed': [['out_legal', 'out_normalised_code_value']],
}, **kwargs).get('out_normalised_code_value', out_normalised_code_value)
x = to_domain_1(x)
if in_reflection:
x = x / 0.9
with domain_range_scale('ignore'):
clog3 = np.select(
(x < log_decoding_CanonLog3(0.04076162, bit_depth, False, False),
x <= log_decoding_CanonLog3(0.105357102, bit_depth, False, False),
x > log_decoding_CanonLog3(0.105357102, bit_depth, False, False)),
(-0.42889912 * np.log10(-x * 14.98325 + 1) + 0.07623209,
2.3069815 * x + 0.073059361,
0.42889912 * np.log10(x * 14.98325 + 1) + 0.069886632))
clog3 = (full_to_legal(clog3, bit_depth)
if out_normalised_code_value else clog3)
return as_float(from_range_1(clog3))
[docs]def log_decoding_CanonLog3(clog3,
bit_depth=10,
in_normalised_code_value=True,
out_reflection=True,
**kwargs):
"""
Defines the *Canon Log 3* log decoding curve / electro-optical transfer
function.
Parameters
----------
clog3 : numeric or array_like
*Canon Log 3* non-linear data.
bit_depth : int, optional
Bit depth used for conversion.
in_normalised_code_value : bool, optional
Whether the *Canon Log 3* non-linear data is encoded with normalised
code values.
out_reflection : bool, optional
Whether the light level :math:`x` to a camera is reflection.
Other Parameters
----------------
\\**kwargs : dict, optional
Keywords arguments for deprecation management.
Returns
-------
numeric or ndarray
Linear data :math:`x`.
Notes
-----
+------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``clog3`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
+------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``x`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
References
----------
:cite:`Canona`
Examples
--------
>>> log_decoding_CanonLog3(34.338936938868677 / 100) # doctest: +ELLIPSIS
0.1800000...
"""
in_normalised_code_value = handle_arguments_deprecation({
'ArgumentRenamed': [['in_legal', 'in_normalised_code_value']],
}, **kwargs).get('in_normalised_code_value', in_normalised_code_value)
clog3 = to_domain_1(clog3)
clog3 = (legal_to_full(clog3, bit_depth)
if in_normalised_code_value else clog3)
x = np.select(
(clog3 < 0.04076162, clog3 <= 0.105357102, clog3 > 0.105357102),
(-(10 ** ((0.07623209 - clog3) / 0.42889912) - 1) / 14.98325,
(clog3 - 0.073059361) / 2.3069815,
(10 ** ((clog3 - 0.069886632) / 0.42889912) - 1) / 14.98325))
if out_reflection:
x = x * 0.9
return as_float(from_range_1(x))