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

# -*- coding: utf-8 -*-
"""
Sony S-Log Encodings
====================

Defines the *Sony S-Log* log encodings:

-   :func:`colour.models.log_encoding_SLog`
-   :func:`colour.models.log_decoding_SLog`
-   :func:`colour.models.log_encoding_SLog2`
-   :func:`colour.models.log_decoding_SLog2`
-   :func:`colour.models.log_encoding_SLog3`
-   :func:`colour.models.log_decoding_SLog3`

References
----------
-   :cite:`SonyCorporation2012a` : Sony Corporation. (2012). S-Log2 Technical
    Paper (pp. 1-9). https://drive.google.com/file/d/\
1Q1RYri6BaxtYYxX0D4zVD6lAmbwmgikc/view?usp=sharing
-   :cite:`SonyCorporationd` : Sony Corporation. (n.d.). Technical Summary
    for S-Gamut3.Cine/S-Log3 and S-Gamut3/S-Log3 (pp. 1-7).
    http://community.sony.com/sony/attachments/sony/\
large-sensor-camera-F5-F55/12359/2/TechnicalSummary_for_S-Gamut3Cine_S-Gamut3_S-Log3_V1_00.pdf
"""

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)

__author__ = 'Colour Developers'
__copyright__ = 'Copyright (C) 2013-2021 - 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_SLog', 'log_decoding_SLog', 'log_encoding_SLog2',
    'log_decoding_SLog2', 'log_encoding_SLog3', 'log_decoding_SLog3'
]


[docs]def log_encoding_SLog(x, bit_depth=10, out_normalised_code_value=True, in_reflection=True): """ Defines the *Sony S-Log* log encoding curve / opto-electronic transfer function. Parameters ---------- x : numeric or array_like Reflection or :math:`IRE / 100` input light level :math:`x` to a camera. bit_depth : int, optional Bit depth used for conversion. out_normalised_code_value : bool, optional Whether the non-linear *Sony S-Log* data :math:`y` is encoded as normalised code values. in_reflection : bool, optional Whether the light level :math:`x` to a camera is reflection. Returns ------- numeric or ndarray Non-linear *Sony S-Log* data :math:`y`. Notes ----- +------------+-----------------------+---------------+ | **Domain** | **Scale - Reference** | **Scale - 1** | +============+=======================+===============+ | ``x`` | [0, 1] | [0, 1] | +------------+-----------------------+---------------+ +------------+-----------------------+---------------+ | **Range** | **Scale - Reference** | **Scale - 1** | +============+=======================+===============+ | ``y`` | [0, 1] | [0, 1] | +------------+-----------------------+---------------+ References ---------- :cite:`SonyCorporation2012a` Examples -------- >>> log_encoding_SLog(0.18) # doctest: +ELLIPSIS 0.3849708... The values of *IRE and CV of S-Log2 @ISO800* table in :cite:`SonyCorporation2012a` are obtained as follows: >>> x = np.array([0, 18, 90]) / 100 >>> np.around(log_encoding_SLog(x, 10, False) * 100).astype(np.int) array([ 3, 38, 65]) >>> np.around(log_encoding_SLog(x) * (2 ** 10 - 1)).astype(np.int) array([ 90, 394, 636]) """ x = to_domain_1(x) if in_reflection: x = x / 0.9 y = np.where( x >= 0, ((0.432699 * np.log10(x + 0.037584) + 0.616596) + 0.03), x * 5 + 0.030001222851889303, ) y = full_to_legal(y, bit_depth) if out_normalised_code_value else y return as_float(from_range_1(y))
[docs]def log_decoding_SLog(y, bit_depth=10, in_normalised_code_value=True, out_reflection=True): """ Defines the *Sony S-Log* log decoding curve / electro-optical transfer function. Parameters ---------- y : numeric or array_like Non-linear *Sony S-Log* data :math:`y`. bit_depth : int, optional Bit depth used for conversion. in_normalised_code_value : bool, optional Whether the non-linear *Sony S-Log* data :math:`y` is encoded as normalised code values. out_reflection : bool, optional Whether the light level :math:`x` to a camera is reflection. Returns ------- numeric or ndarray Reflection or :math:`IRE / 100` input light level :math:`x` to a camera. Notes ----- +------------+-----------------------+---------------+ | **Domain** | **Scale - Reference** | **Scale - 1** | +============+=======================+===============+ | ``y`` | [0, 1] | [0, 1] | +------------+-----------------------+---------------+ +------------+-----------------------+---------------+ | **Range** | **Scale - Reference** | **Scale - 1** | +============+=======================+===============+ | ``x`` | [0, 1] | [0, 1] | +------------+-----------------------+---------------+ References ---------- :cite:`SonyCorporation2012a` Examples -------- >>> log_decoding_SLog(0.384970815928670) # doctest: +ELLIPSIS 0.1... """ y = to_domain_1(y) x = legal_to_full(y, bit_depth) if in_normalised_code_value else y with domain_range_scale('ignore'): x = np.where( y >= log_encoding_SLog(0.0, bit_depth, in_normalised_code_value), 10 ** ((x - 0.616596 - 0.03) / 0.432699) - 0.037584, (x - 0.030001222851889303) / 5.0, ) if out_reflection: x = x * 0.9 return as_float(from_range_1(x))
[docs]def log_encoding_SLog2(x, bit_depth=10, out_normalised_code_value=True, in_reflection=True): """ Defines the *Sony S-Log2* log encoding curve / opto-electronic transfer function. Parameters ---------- x : numeric or array_like Reflection or :math:`IRE / 100` input light level :math:`x` to a camera. bit_depth : int, optional Bit depth used for conversion. out_normalised_code_value : bool, optional Whether the non-linear *Sony S-Log2* data :math:`y` is encoded as normalised code values. in_reflection : bool, optional Whether the light level :math:`x` to a camera is reflection. Returns ------- numeric or ndarray Non-linear *Sony S-Log2* data :math:`y`. Notes ----- +------------+-----------------------+---------------+ | **Domain** | **Scale - Reference** | **Scale - 1** | +============+=======================+===============+ | ``x`` | [0, 1] | [0, 1] | +------------+-----------------------+---------------+ +------------+-----------------------+---------------+ | **Range** | **Scale - Reference** | **Scale - 1** | +============+=======================+===============+ | ``y`` | [0, 1] | [0, 1] | +------------+-----------------------+---------------+ References ---------- :cite:`SonyCorporation2012a` Examples -------- >>> log_encoding_SLog2(0.18) # doctest: +ELLIPSIS 0.3395325... The values of *IRE and CV of S-Log2 @ISO800* table in :cite:`SonyCorporation2012a` are obtained as follows: >>> x = np.array([0, 18, 90]) / 100 >>> np.around(log_encoding_SLog2(x, 10, False) * 100).astype(np.int) array([ 3, 32, 59]) >>> np.around(log_encoding_SLog2(x) * (2 ** 10 - 1)).astype(np.int) array([ 90, 347, 582]) """ return log_encoding_SLog(x * 155 / 219, bit_depth, out_normalised_code_value, in_reflection)
[docs]def log_decoding_SLog2(y, bit_depth=10, in_normalised_code_value=True, out_reflection=True): """ Defines the *Sony S-Log2* log decoding curve / electro-optical transfer function. Parameters ---------- y : numeric or array_like Non-linear *Sony S-Log2* data :math:`y`. bit_depth : int, optional Bit depth used for conversion. in_normalised_code_value : bool, optional Whether the non-linear *Sony S-Log2* data :math:`y` is encoded as normalised code values. out_reflection : bool, optional Whether the light level :math:`x` to a camera is reflection. Returns ------- numeric or ndarray Reflection or :math:`IRE / 100` input light level :math:`x` to a camera. Notes ----- +------------+-----------------------+---------------+ | **Domain** | **Scale - Reference** | **Scale - 1** | +============+=======================+===============+ | ``y`` | [0, 1] | [0, 1] | +------------+-----------------------+---------------+ +------------+-----------------------+---------------+ | **Range** | **Scale - Reference** | **Scale - 1** | +============+=======================+===============+ | ``x`` | [0, 1] | [0, 1] | +------------+-----------------------+---------------+ References ---------- :cite:`SonyCorporation2012a` Examples -------- >>> log_decoding_SLog2(0.339532524633774) # doctest: +ELLIPSIS 0.1... """ return 219 * log_decoding_SLog(y, bit_depth, in_normalised_code_value, out_reflection) / 155
[docs]def log_encoding_SLog3(x, bit_depth=10, out_normalised_code_value=True, in_reflection=True): """ Defines the *Sony S-Log3* log encoding curve / opto-electronic transfer function. Parameters ---------- x : numeric or array_like Reflection or :math:`IRE / 100` input light level :math:`x` to a camera. bit_depth : int, optional Bit depth used for conversion. out_normalised_code_value : bool, optional Whether the non-linear *Sony S-Log3* data :math:`y` is encoded as normalised code values. in_reflection : bool, optional Whether the light level :math:`x` to a camera is reflection. Returns ------- numeric or ndarray Non-linear *Sony S-Log3* data :math:`y`. Notes ----- +------------+-----------------------+---------------+ | **Domain** | **Scale - Reference** | **Scale - 1** | +============+=======================+===============+ | ``x`` | [0, 1] | [0, 1] | +------------+-----------------------+---------------+ +------------+-----------------------+---------------+ | **Range** | **Scale - Reference** | **Scale - 1** | +============+=======================+===============+ | ``y`` | [0, 1] | [0, 1] | +------------+-----------------------+---------------+ References ---------- :cite:`SonyCorporationd` Examples -------- >>> log_encoding_SLog3(0.18) # doctest: +ELLIPSIS 0.4105571... The values of *S-Log3 10bit code values (18%, 90%)* table in :cite:`SonyCorporationd` are obtained as follows: >>> x = np.array([0, 18, 90]) / 100 >>> np.around(log_encoding_SLog3(x, 10, False) * 100).astype(np.int) array([ 4, 41, 61]) >>> np.around(log_encoding_SLog3(x) * (2 ** 10 - 1)).astype(np.int) array([ 95, 420, 598]) """ x = to_domain_1(x) if not in_reflection: x = x * 0.9 y = np.where( x >= 0.01125000, (420 + np.log10((x + 0.01) / (0.18 + 0.01)) * 261.5) / 1023, (x * (171.2102946929 - 95) / 0.01125000 + 95) / 1023, ) y = y if out_normalised_code_value else legal_to_full(y, bit_depth) return as_float(from_range_1(y))
[docs]def log_decoding_SLog3(y, bit_depth=10, in_normalised_code_value=True, out_reflection=True): """ Defines the *Sony S-Log3* log decoding curve / electro-optical transfer function. Parameters ---------- y : numeric or array_like Non-linear *Sony S-Log3* data :math:`y`. bit_depth : int, optional Bit depth used for conversion. in_normalised_code_value : bool, optional Whether the non-linear *Sony S-Log3* data :math:`y` is encoded as normalised code values. out_reflection : bool, optional Whether the light level :math:`x` to a camera is reflection. Returns ------- numeric or ndarray Reflection or :math:`IRE / 100` input light level :math:`x` to a camera. Notes ----- +------------+-----------------------+---------------+ | **Domain** | **Scale - Reference** | **Scale - 1** | +============+=======================+===============+ | ``y`` | [0, 1] | [0, 1] | +------------+-----------------------+---------------+ +------------+-----------------------+---------------+ | **Range** | **Scale - Reference** | **Scale - 1** | +============+=======================+===============+ | ``x`` | [0, 1] | [0, 1] | +------------+-----------------------+---------------+ References ---------- :cite:`SonyCorporationd` Examples -------- >>> log_decoding_SLog3(0.410557184750733) # doctest: +ELLIPSIS 0.1... """ y = to_domain_1(y) y = y if in_normalised_code_value else full_to_legal(y, bit_depth) x = np.where( y >= 171.2102946929 / 1023, ((10 ** ((y * 1023 - 420) / 261.5)) * (0.18 + 0.01) - 0.01), (y * 1023 - 95) * 0.01125000 / (171.2102946929 - 95), ) if not out_reflection: x = x / 0.9 return as_float(from_range_1(x))