Source code for colour.models.rgb.transfer_functions.blackmagic_design
"""
Blackmagic Design Transfer Functions
====================================
Defines the *Blackmagic Design* colour component transfer functions:
- :func:`colour.models.oetf_BlackmagicFilmGeneration5`
- :func:`colour.models.oetf_inverse_BlackmagicFilmGeneration5`
References
----------
- :cite:`BlackmagicDesign2021` : Blackmagic Design. (2021). Blackmagic
Generation 5 Color Science. https://drive.google.com/file/d/\
1FF5WO2nvI9GEWb4_EntrBoV9ZIuFToZd/view
"""
from __future__ import annotations
import numpy as np
from colour.hints import ArrayLike, NDArrayFloat
from colour.utilities import Structure, as_float, from_range_1, to_domain_1
__author__ = "Colour Developers"
__copyright__ = "Copyright 2013 Colour Developers"
__license__ = "BSD-3-Clause - https://opensource.org/licenses/BSD-3-Clause"
__maintainer__ = "Colour Developers"
__email__ = "colour-developers@colour-science.org"
__status__ = "Production"
__all__ = [
"CONSTANTS_BLACKMAGIC_FILM_GENERATION_5",
"oetf_BlackmagicFilmGeneration5",
"oetf_inverse_BlackmagicFilmGeneration5",
]
CONSTANTS_BLACKMAGIC_FILM_GENERATION_5: Structure = Structure(
A=0.08692876065491224,
B=0.005494072432257808,
C=0.5300133392291939,
D=8.283605932402494,
E=0.09246575342465753,
LIN_CUT=0.005,
)
"""*Blackmagic Film Generation 5* colour component transfer functions constants."""
[docs]
def oetf_BlackmagicFilmGeneration5(
x: ArrayLike,
constants: Structure = CONSTANTS_BLACKMAGIC_FILM_GENERATION_5,
) -> NDArrayFloat:
"""
Define the *Blackmagic Film Generation 5* opto-electronic transfer
function (OETF).
Parameters
----------
x
Linear light value :math`x`.
constants
*Blackmagic Film Generation 5* constants.
Returns
-------
:class:`numpy.ndarray`
Encoded value :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:`BlackmagicDesign2021`
Examples
--------
>>> oetf_BlackmagicFilmGeneration5(0.18) # doctest: +ELLIPSIS
0.3835616...
"""
x = to_domain_1(x)
A = constants.A
B = constants.B
C = constants.C
D = constants.D
E = constants.E
LIN_CUT = constants.LIN_CUT
V_out = np.where(
x < LIN_CUT,
D * x + E,
A * np.log(x + B) + C,
)
return as_float(from_range_1(V_out))
[docs]
def oetf_inverse_BlackmagicFilmGeneration5(
y: ArrayLike,
constants: Structure = CONSTANTS_BLACKMAGIC_FILM_GENERATION_5,
) -> NDArrayFloat:
"""
Define the *Blackmagic Film Generation 5* inverse opto-electronic transfer
function (OETF).
Parameters
----------
y
Encoded value :math:`y`.
constants
*Blackmagic Film Generation 5* constants.
Returns
-------
:class:`numpy.ndarray`
Linear light value :math`x`.
Notes
-----
+------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``y`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
+------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``x`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
References
----------
:cite:`BlackmagicDesign2021`
Examples
--------
>>> oetf_inverse_BlackmagicFilmGeneration5(0.38356164383561653)
... # doctest: +ELLIPSIS
0.1799999...
"""
y = to_domain_1(y)
A = constants.A
B = constants.B
C = constants.C
D = constants.D
E = constants.E
LIN_CUT = constants.LIN_CUT
LOG_CUT = D * LIN_CUT + E
x = np.where(
y < LOG_CUT,
(y - E) / D,
np.exp((y - C) / A) - B,
)
return as_float(from_range_1(x))