# -*- coding: utf-8 -*-
"""
:math:`\\Delta E'` - Delta E Colour Difference - Luo, Cui and Li (2006)
======================================================================
Defines :math:`\\Delta E'` colour difference computation objects based on
*Luo et al. (2006)* *CAM02-LCD*, *CAM02-SCD*, and *CAM02-UCS* colourspaces:
- :func:`colour.difference.delta_E_CAM02LCD`
- :func:`colour.difference.delta_E_CAM02SCD`
- :func:`colour.difference.delta_E_CAM02UCS`
See Also
--------
`CAM02-LCD, CAM02-SCD, and CAM02-UCS Colourspaces Jupyter Notebook
<http://nbviewer.jupyter.org/github/colour-science/colour-notebooks/\
blob/master/notebooks/models/ucs_luo2006.ipynb>`_
References
----------
- :cite:`Luo2006b` : Luo, M. R., Cui, G., & Li, C. (2006). Uniform colour
spaces based on CIECAM02 colour appearance model. Color Research &
Application, 31(4), 320-330. doi:10.1002/col.20227
"""
from __future__ import division, unicode_literals
import numpy as np
from colour.utilities import tsplit
from colour.models.cam02_ucs import COEFFICIENTS_UCS_LUO2006
__author__ = 'Colour Developers'
__copyright__ = 'Copyright (C) 2013-2019 - Colour Developers'
__license__ = 'New BSD License - https://opensource.org/licenses/BSD-3-Clause'
__maintainer__ = 'Colour Developers'
__email__ = 'colour-science@googlegroups.com'
__status__ = 'Production'
__all__ = [
'delta_E_Luo2006', 'delta_E_CAM02LCD', 'delta_E_CAM02SCD',
'delta_E_CAM02UCS'
]
def delta_E_Luo2006(Jpapbp_1, Jpapbp_2, coefficients):
"""
Returns the difference :math:`\\Delta E'` between two given
*Luo et al. (2006)* *CAM02-LCD*, *CAM02-SCD*, or *CAM02-UCS* colourspaces
:math:`J'a'b'` arrays.
Parameters
----------
Jpapbp_1 : array_like
Standard / reference *Luo et al. (2006)* *CAM02-LCD*, *CAM02-SCD*, or
*CAM02-UCS* colourspaces :math:`J'a'b'` array.
Jpapbp_2 : array_like
Sample / test *Luo et al. (2006)* *CAM02-LCD*, *CAM02-SCD*, or
*CAM02-UCS* colourspaces :math:`J'a'b'` array.
coefficients : array_like
Coefficients of one of the *Luo et al. (2006)* *CAM02-LCD*,
*CAM02-SCD*, or *CAM02-UCS* colourspaces.
Returns
-------
numeric or ndarray
Colour difference :math:`\\Delta E'`.
Notes
-----
+--------------+------------------------+--------------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+==============+========================+====================+
| ``Jpapbp_1`` | ``Jp_1`` : [0, 100] | ``Jp_1`` : [0, 1] |
| | | |
| | ``ap_1`` : [-100, 100] | ``ap_1`` : [-1, 1] |
| | | |
| | ``bp_1`` : [-100, 100] | ``bp_1`` : [-1, 1] |
+--------------+------------------------+--------------------+
| ``Jpapbp_2`` | ``Jp_2`` : [0, 100] | ``Jp_2`` : [0, 1] |
| | | |
| | ``ap_2`` : [-100, 100] | ``ap_2`` : [-1, 1] |
| | | |
| | ``bp_2`` : [-100, 100] | ``bp_2`` : [-1, 1] |
+--------------+------------------------+--------------------+
Examples
--------
>>> Jpapbp_1 = np.array([54.90433134, -0.08450395, -0.06854831])
>>> Jpapbp_2 = np.array([54.80352754, -3.96940084, -13.57591013])
>>> delta_E_Luo2006(Jpapbp_1, Jpapbp_2,
... COEFFICIENTS_UCS_LUO2006['CAM02-LCD'])
... # doctest: +ELLIPSIS
0.0001034...
"""
J_p_1, a_p_1, b_p_1 = tsplit(Jpapbp_1)
J_p_2, a_p_2, b_p_2 = tsplit(Jpapbp_2)
K_L, _c_1, _c_2 = tsplit(coefficients)
d_E = np.sqrt(((J_p_1 - J_p_2) / K_L) ** 2 + (a_p_1 - a_p_2) ** 2 +
(b_p_1 - b_p_2) ** 2)
return d_E
[docs]def delta_E_CAM02LCD(Jpapbp_1, Jpapbp_2):
"""
Returns the difference :math:`\\Delta E'` between two given
*Luo et al. (2006)* *CAM02-LCD* colourspaces :math:`J'a'b'` arrays.
Parameters
----------
Jpapbp_1 : array_like
Standard / reference *Luo et al. (2006)* *CAM02-LCD* colourspaces
:math:`J'a'b'` array.
Jpapbp_2 : array_like
Sample / test *Luo et al. (2006)* *CAM02-LCD* colourspaces
:math:`J'a'b'` array.
Returns
-------
numeric or ndarray
Colour difference :math:`\\Delta E'`.
Notes
-----
+--------------+------------------------+--------------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+==============+========================+====================+
| ``Jpapbp_1`` | ``Jp_1`` : [0, 100] | ``Jp_1`` : [0, 1] |
| | | |
| | ``ap_1`` : [-100, 100] | ``ap_1`` : [-1, 1] |
| | | |
| | ``bp_1`` : [-100, 100] | ``bp_1`` : [-1, 1] |
+--------------+------------------------+--------------------+
| ``Jpapbp_2`` | ``Jp_2`` : [0, 100] | ``Jp_2`` : [0, 1] |
| | | |
| | ``ap_2`` : [-100, 100] | ``ap_2`` : [-1, 1] |
| | | |
| | ``bp_2`` : [-100, 100] | ``bp_2`` : [-1, 1] |
+--------------+------------------------+--------------------+
References
----------
:cite:`Luo2006b`
Examples
--------
>>> Jpapbp_1 = np.array([54.90433134, -0.08450395, -0.06854831])
>>> Jpapbp_2 = np.array([54.80352754, -3.96940084, -13.57591013])
>>> delta_E_CAM02LCD(Jpapbp_1, Jpapbp_2) # doctest: +ELLIPSIS
14.0555464...
"""
return delta_E_Luo2006(Jpapbp_1, Jpapbp_2,
COEFFICIENTS_UCS_LUO2006['CAM02-LCD'])
[docs]def delta_E_CAM02SCD(Jpapbp_1, Jpapbp_2):
"""
Returns the difference :math:`\\Delta E'` between two given
*Luo et al. (2006)* *CAM02-SCD* colourspaces :math:`J'a'b'` arrays.
Parameters
----------
Jpapbp_1 : array_like
Standard / reference *Luo et al. (2006)* *CAM02-SCD* colourspaces
:math:`J'a'b'` array.
Jpapbp_2 : array_like
Sample / test *Luo et al. (2006)* *CAM02-SCD* colourspaces
:math:`J'a'b'` array.
Returns
-------
numeric or ndarray
Colour difference :math:`\\Delta E'`.
Notes
-----
+--------------+------------------------+--------------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+==============+========================+====================+
| ``Jpapbp_1`` | ``Jp_1`` : [0, 100] | ``Jp_1`` : [0, 1] |
| | | |
| | ``ap_1`` : [-100, 100] | ``ap_1`` : [-1, 1] |
| | | |
| | ``bp_1`` : [-100, 100] | ``bp_1`` : [-1, 1] |
+--------------+------------------------+--------------------+
| ``Jpapbp_2`` | ``Jp_2`` : [0, 100] | ``Jp_2`` : [0, 1] |
| | | |
| | ``ap_2`` : [-100, 100] | ``ap_2`` : [-1, 1] |
| | | |
| | ``bp_2`` : [-100, 100] | ``bp_2`` : [-1, 1] |
+--------------+------------------------+--------------------+
References
----------
:cite:`Luo2006b`
Examples
--------
>>> Jpapbp_1 = np.array([54.90433134, -0.08450395, -0.06854831])
>>> Jpapbp_2 = np.array([54.80352754, -3.96940084, -13.57591013])
>>> delta_E_CAM02SCD(Jpapbp_1, Jpapbp_2) # doctest: +ELLIPSIS
14.0551718...
"""
return delta_E_Luo2006(Jpapbp_1, Jpapbp_2,
COEFFICIENTS_UCS_LUO2006['CAM02-SCD'])
[docs]def delta_E_CAM02UCS(Jpapbp_1, Jpapbp_2):
"""
Returns the difference :math:`\\Delta E'` between two given
*Luo et al. (2006)* *CAM02-UCS* colourspaces :math:`J'a'b'` arrays.
Parameters
----------
Jpapbp_1 : array_like
Standard / reference *Luo et al. (2006)* *CAM02-UCS* colourspaces
:math:`J'a'b'` array.
Jpapbp_2 : array_like
Sample / test *Luo et al. (2006)* *CAM02-UCS* colourspaces
:math:`J'a'b'` array.
Returns
-------
numeric or ndarray
Colour difference :math:`\\Delta E'`.
Notes
-----
+--------------+------------------------+--------------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+==============+========================+====================+
| ``Jpapbp_1`` | ``Jp_1`` : [0, 100] | ``Jp_1`` : [0, 1] |
| | | |
| | ``ap_1`` : [-100, 100] | ``ap_1`` : [-1, 1] |
| | | |
| | ``bp_1`` : [-100, 100] | ``bp_1`` : [-1, 1] |
+--------------+------------------------+--------------------+
| ``Jpapbp_2`` | ``Jp_2`` : [0, 100] | ``Jp_2`` : [0, 1] |
| | | |
| | ``ap_2`` : [-100, 100] | ``ap_2`` : [-1, 1] |
| | | |
| | ``bp_2`` : [-100, 100] | ``bp_2`` : [-1, 1] |
+--------------+------------------------+--------------------+
References
----------
:cite:`Luo2006b`
Examples
--------
>>> Jpapbp_1 = np.array([54.90433134, -0.08450395, -0.06854831])
>>> Jpapbp_2 = np.array([54.80352754, -3.96940084, -13.57591013])
>>> delta_E_CAM02UCS(Jpapbp_1, Jpapbp_2) # doctest: +ELLIPSIS
14.0552982...
"""
return delta_E_Luo2006(Jpapbp_1, Jpapbp_2,
COEFFICIENTS_UCS_LUO2006['CAM02-UCS'])