Source code for colour.models.rgb.transfer_functions.dcdm
"""
Digital Cinema Distribution Master (DCDM)
=========================================
Defines the *DCDM* electro-optical transfer function (EOTF) and its
inverse:
- :func:`colour.models.eotf_inverse_DCDM`
- :func:`colour.models.eotf_DCDM`
References
----------
- :cite:`DigitalCinemaInitiatives2007b` : Digital Cinema Initiatives. (2007).
Digital Cinema System Specification - Version 1.1.
http://www.dcimovies.com/archives/spec_v1_1/\
DCI_DCinema_System_Spec_v1_1.pdf
- :cite:`SocietyofMotionPictureandTelevisionEngineers2019` : Society of
Motion Picture and Television Engineers. (2019). ST 428-1:2019 - D-Cinema
Distribution Master — Image Characteristic. doi:10.5594/SMPTE.ST428-1.2019
"""
from __future__ import annotations
import numpy as np
from colour.algebra import spow
from colour.hints import ArrayLike, NDArrayFloat, NDArrayReal
from colour.utilities import as_float, as_float_array, as_int
__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__ = [
"eotf_inverse_DCDM",
"eotf_DCDM",
]
[docs]
def eotf_inverse_DCDM(XYZ: ArrayLike, out_int: bool = False) -> NDArrayReal:
"""
Define the *DCDM* inverse electro-optical transfer function (EOTF).
Parameters
----------
XYZ
*CIE XYZ* tristimulus values.
out_int
Whether to return value as int code value or float equivalent of a
code value at a given bit-depth.
Returns
-------
:class:`numpy.ndarray`
Non-linear *CIE XYZ'* tristimulus values.
Warnings
--------
*DCDM* is an absolute transfer function.
Notes
-----
- *DCDM* is an absolute transfer function, thus the domain and range
values for the *Reference* and *1* scales are only indicative that the
data is not affected by scale transformations.
+----------------+-----------------------+---------------+
| **Domain \\*** | **Scale - Reference** | **Scale - 1** |
+================+=======================+===============+
| ``XYZ`` | ``UN`` | ``UN`` |
+----------------+-----------------------+---------------+
+----------------+-----------------------+---------------+
| **Range \\*** | **Scale - Reference** | **Scale - 1** |
+================+=======================+===============+
| ``XYZ_p`` | ``UN`` | ``UN`` |
+----------------+-----------------------+---------------+
\\* This definition has an output int switch, thus the domain-range
scale information is only given for the floating point mode.
References
----------
:cite:`DigitalCinemaInitiatives2007b`
Examples
--------
>>> eotf_inverse_DCDM(0.18) # doctest: +ELLIPSIS
0.1128186...
>>> eotf_inverse_DCDM(0.18, out_int=True)
462
"""
XYZ = as_float_array(XYZ)
XYZ_p = spow(XYZ / 52.37, 1 / 2.6)
if out_int:
return as_int(np.round(4095 * XYZ_p))
else:
return as_float(XYZ_p)
[docs]
def eotf_DCDM(
XYZ_p: ArrayLike,
in_int: bool = False,
) -> NDArrayFloat:
"""
Define the *DCDM* electro-optical transfer function (EOTF).
Parameters
----------
XYZ_p
Non-linear *CIE XYZ'* tristimulus values.
in_int
Whether to treat the input value as int code value or float
equivalent of a code value at a given bit-depth.
Returns
-------
:class:`numpy.ndarray`
*CIE XYZ* tristimulus values.
Warnings
--------
*DCDM* is an absolute transfer function.
Notes
-----
- *DCDM* is an absolute transfer function, thus the domain and range
values for the *Reference* and *1* scales are only indicative that the
data is not affected by scale transformations.
+----------------+-----------------------+---------------+
| **Domain \\*** | **Scale - Reference** | **Scale - 1** |
+================+=======================+===============+
| ``XYZ_p`` | ``UN`` | ``UN`` |
+----------------+-----------------------+---------------+
+----------------+-----------------------+---------------+
| **Range \\*** | **Scale - Reference** | **Scale - 1** |
+================+=======================+===============+
| ``XYZ`` | ``UN`` | ``UN`` |
+----------------+-----------------------+---------------+
\\* This definition has an input int switch, thus the domain-range
scale information is only given for the floating point mode.
References
----------
:cite:`DigitalCinemaInitiatives2007b`
Examples
--------
>>> eotf_DCDM(0.11281860951766724) # doctest: +ELLIPSIS
0.18...
>>> eotf_DCDM(462, in_int=True) # doctest: +ELLIPSIS
0.18...
"""
XYZ_p = as_float_array(XYZ_p)
if in_int:
XYZ_p = XYZ_p / 4095
XYZ = 52.37 * spow(XYZ_p, 2.6)
return as_float(XYZ)