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

# -*- coding: utf-8 -*-
"""
Digital Cinema Distribution Master (DCDM)
=========================================

Defines the *DCDM* electro-optical transfer function (EOTF / EOCF) 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
"""

from __future__ import division, unicode_literals

import numpy as np

from colour.algebra import spow
from colour.constants import DEFAULT_INT_DTYPE
from colour.utilities import from_range_1, to_domain_1

__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__ = ['eotf_inverse_DCDM', 'eotf_DCDM']


[docs]def eotf_inverse_DCDM(XYZ, out_int=False): """ Defines the *DCDM* inverse electro-optical transfer function (EOTF / EOCF). Parameters ---------- XYZ : numeric or array_like *CIE XYZ* tristimulus values. out_int : bool, optional Whether to return value as integer code value or float equivalent of a code value at a given bit depth. Returns ------- numeric or 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`` | [0, 1] | [0, 1] | +----------------+-----------------------+---------------+ +----------------+-----------------------+---------------+ | **Range \\*** | **Scale - Reference** | **Scale - 1** | +================+=======================+===============+ | ``XYZ_p`` | [0, 1] | [0, 1] | +----------------+-----------------------+---------------+ \\* This definition has an output integer 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 = to_domain_1(XYZ) XYZ_p = spow(XYZ / 52.37, 1 / 2.6) if out_int: return np.round(4095 * XYZ_p).astype(DEFAULT_INT_DTYPE) else: return from_range_1(XYZ_p)
[docs]def eotf_DCDM(XYZ_p, in_int=False): """ Defines the *DCDM* electro-optical transfer function (EOTF / EOCF). Parameters ---------- XYZ_p : numeric or array_like Non-linear *CIE XYZ'* tristimulus values. in_int : bool, optional Whether to treat the input value as integer code value or float equivalent of a code value at a given bit depth. Returns ------- numeric or 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`` | [0, 1] | [0, 1] | +----------------+-----------------------+---------------+ +----------------+-----------------------+---------------+ | **Range \\*** | **Scale - Reference** | **Scale - 1** | +================+=======================+===============+ | ``XYZ`` | [0, 1] | [0, 1] | +----------------+-----------------------+---------------+ \\* This definition has an input integer 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 = to_domain_1(XYZ_p) if in_int: XYZ_p = XYZ_p / 4095 XYZ = 52.37 * spow(XYZ_p, 2.6) return from_range_1(XYZ)