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

# -*- 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`

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. (2016). 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 September 25, 2014, 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) 2013-2020 - Colour Developers'
__license__ = 'New BSD License - https://opensource.org/licenses/BSD-3-Clause'
__maintainer__ = 'Colour Developers'
__email__ = 'colour-developers@colour-science.org'
__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))