Source code for colour.difference.huang2015

"""
Huang et al. (2015) Power-Functions
===================================

Defines the *Huang, Cui, Melgosa, Sanchez-Maranon, Li, Luo and Liu (2015)*
power-functions improving the performance of colour-difference formulas:

-   :func:`colour.difference.power_function_Huang2015`

References
----------
-   :cite:`Huang2015` : Huang, M., Cui, G., Melgosa, M., Sanchez-Maranon, M.,
    Li, C., Luo, M. R., & Liu, H. (2015). Power functions improving the
    performance of color-difference formulas. Optical Society of America,
    23(1), 597-610. doi:10.1364/OE.23.000597
-   :cite:`Li2017` : Li, C., Li, Z., Wang, Z., Xu, Y., Luo, M. R., Cui, G.,
    Melgosa, M., Brill, M. H., & Pointer, M. (2017). Comprehensive color
    solutions: CAM16, CAT16, and CAM16-UCS. Color Research & Application,
    42(6), 703-718. doi:10.1002/col.22131
"""

from __future__ import annotations

import numpy as np

from colour.hints import ArrayLike, Literal, NDArrayFloat
from colour.utilities import CanonicalMapping, tsplit, validate_method

__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__ = [
    "power_function_Huang2015",
]

COEFFICIENTS_HUANG2015: CanonicalMapping = CanonicalMapping(
    {
        "CIE 1976": np.array([1.26, 0.55]),
        "CIE 1994": np.array([1.41, 0.70]),
        "CIE 2000": np.array([1.43, 0.70]),
        "CMC": np.array([1.34, 0.66]),
        "CAM02-LCD": np.array([1.00, 0.85]),
        "CAM02-SCD": np.array([1.45, 0.75]),
        "CAM02-UCS": np.array([1.30, 0.75]),
        "CAM16-UCS": np.array([1.41, 0.63]),
        "DIN99d": np.array([1.28, 0.74]),
        "OSA": np.array([3.32, 0.62]),
        "OSA-GP-Euclidean": np.array([1.52, 0.76]),
        "ULAB": np.array([1.17, 0.69]),
    }
)
COEFFICIENTS_HUANG2015.__doc__ = """
*Huang et al. (2015)* power-functions coefficients.

References
----------
:cite:`Huang2015`, :cite:`Li2017`

Notes
-----
-   :cite:`Li2017` does not give the coefficients for the *CAM16-LCD* and
    *CAM16-SCD* colourspaces. *Ronnie Luo* has been contacted to know if they
    have been computed.

Aliases:

-   'cie1976': 'CIE 1976'
-   'cie1994': 'CIE 1994'
-   'cie2000': 'CIE 2000'
"""
COEFFICIENTS_HUANG2015["cie1976"] = COEFFICIENTS_HUANG2015["CIE 1976"]
COEFFICIENTS_HUANG2015["cie1994"] = COEFFICIENTS_HUANG2015["CIE 1994"]
COEFFICIENTS_HUANG2015["cie2000"] = COEFFICIENTS_HUANG2015["CIE 2000"]


[docs] def power_function_Huang2015( d_E: ArrayLike, coefficients: ( Literal[ "CIE 1976", "CIE 1994", "CIE 2000", "CMC", "CAM02-LCD", "CAM02-SCD", "CAM16-UCS", "DIN99d", "OSA", "OSA-GP-Euclidean", "ULAB", ] | str ) = "CIE 2000", ) -> NDArrayFloat: """ Improve the performance of the :math:`\\Delta E` value for given coefficients using *Huang, Cui, Melgosa, Sanchez-Maranon, Li, Luo and Liu (2015)* power-function: :math:`d_E^{\\prime}=a*d_{E^b}`. Parameters ---------- d_E Computed colour difference array :math:`\\Delta E`. coefficients Coefficients for the power-function. Returns ------- :class:`numpy.ndarray` Improved math:`\\Delta E` value. References ---------- :cite:`Huang2015`, :cite:`Li2017` Examples -------- >>> d_E = np.array([2.0425, 2.8615, 3.4412]) >>> power_function_Huang2015(d_E) # doctest: +ELLIPSIS array([ 2.3574879..., 2.9850503..., 3.3965106...]) """ coefficients = validate_method( coefficients, tuple(COEFFICIENTS_HUANG2015), '"{0}" coefficients are invalid, they must be one of {1}!', ) a, b = tsplit(COEFFICIENTS_HUANG2015[coefficients]) d_E_p = a * d_E**b return d_E_p