#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Colour Matching Functions Transformations
=========================================
Defines various educational objects for colour matching functions
transformations:
- :func:`RGB_2_degree_cmfs_to_XYZ_2_degree_cmfs`
- :func:`RGB_10_degree_cmfs_to_XYZ_10_degree_cmfs`
- :func:`RGB_10_degree_cmfs_to_LMS_10_degree_cmfs`
- :func:`LMS_2_degree_cmfs_to_XYZ_2_degree_cmfs`
See Also
--------
`Colour Matching Functions IPython Notebook
<http://nbviewer.ipython.org/github/colour-science/colour-ipython/blob/master/notebooks/colorimetry/cmfs.ipynb>`_ # noqa
"""
from __future__ import division, unicode_literals
import numpy as np
from colour.colorimetry import LMS_CMFS, RGB_CMFS, PHOTOPIC_LEFS
__author__ = 'Colour Developers'
__copyright__ = 'Copyright (C) 2013 - 2014 - Colour Developers'
__license__ = 'New BSD License - http://opensource.org/licenses/BSD-3-Clause'
__maintainer__ = 'Colour Developers'
__email__ = 'colour-science@googlegroups.com'
__status__ = 'Production'
__all__ = ['RGB_2_degree_cmfs_to_XYZ_2_degree_cmfs',
'RGB_10_degree_cmfs_to_XYZ_10_degree_cmfs',
'RGB_10_degree_cmfs_to_LMS_10_degree_cmfs',
'LMS_2_degree_cmfs_to_XYZ_2_degree_cmfs']
[docs]def RGB_2_degree_cmfs_to_XYZ_2_degree_cmfs(wavelength):
"""
Converts *Wright & Guild 1931 2 Degree RGB CMFs* colour matching functions
into the *CIE 1931 2 Degree Standard Observer* colour matching functions.
Parameters
----------
wavelength : numeric
Wavelength :math:`\lambda` in nm.
Returns
-------
ndarray, (3,)
*CIE 1931 2 Degree Standard Observer* spectral tristimulus values.
Raises
------
KeyError
If wavelength :math:`\lambda` is not available in the colour matching
functions.
See Also
--------
:attr:`colour.colorimetry.dataset.cmfs.RGB_CMFS`
Notes
-----
- Data for the *CIE 1931 2 Degree Standard Observer* already exists,
this definition is intended for educational purpose.
References
----------
.. [1] **Wyszecki & Stiles**,
*Color Science - Concepts and Methods Data and Formulae -
Second Edition*,
Wiley Classics Library Edition, published 2000,
ISBN-10: 0-471-39918-3,
pages 138, 139.
Examples
--------
>>> RGB_2_degree_cmfs_to_XYZ_2_degree_cmfs(700) # doctest: +ELLIPSIS
array([ 0.0113577..., 0.004102 , 0. ])
"""
cmfs = RGB_CMFS.get('Wright & Guild 1931 2 Degree RGB CMFs')
r_bar, g_bar, b_bar = cmfs.r_bar.get(wavelength), cmfs.g_bar.get(
wavelength), cmfs.b_bar.get(wavelength)
if None in (r_bar, g_bar, b_bar):
raise KeyError(('"{0} nm" wavelength not available in "{1}" colour '
'matching functions with "{2}" shape!').format(
wavelength, cmfs.name, cmfs.shape))
r = r_bar / (r_bar + g_bar + b_bar)
g = g_bar / (r_bar + g_bar + b_bar)
b = b_bar / (r_bar + g_bar + b_bar)
x = ((0.49000 * r + 0.31000 * g + 0.20000 * b) /
(0.66697 * r + 1.13240 * g + 1.20063 * b))
y = ((0.17697 * r + 0.81240 * g + 0.01063 * b) /
(0.66697 * r + 1.13240 * g + 1.20063 * b))
z = ((0.00000 * r + 0.01000 * g + 0.99000 * b) /
(0.66697 * r + 1.13240 * g + 1.20063 * b))
V = PHOTOPIC_LEFS.get('CIE 1924 Photopic Standard Observer').clone()
V.align(cmfs.shape)
L = V.get(wavelength)
x_bar = x / y * L
y_bar = L
z_bar = z / y * L
return np.array([x_bar, y_bar, z_bar])
[docs]def RGB_10_degree_cmfs_to_XYZ_10_degree_cmfs(wavelength):
"""
Converts *Stiles & Burch 1959 10 Degree RGB CMFs* colour matching
functions into the *CIE 1964 10 Degree Standard Observer* colour matching
functions.
Parameters
----------
wavelength : numeric
Wavelength :math:`\lambda` in nm.
Returns
-------
ndarray, (3,)
*CIE 1964 10 Degree Standard Observer* spectral tristimulus values.
Raises
------
KeyError
If wavelength :math:`\lambda` is not available in the colour matching
functions.
See Also
--------
:attr:`colour.colorimetry.dataset.cmfs.RGB_CMFS`
Notes
-----
- Data for the *CIE 1964 10 Degree Standard Observer* already exists,
this definition is intended for educational purpose.
References
----------
.. [2] **Wyszecki & Stiles**,
*Color Science - Concepts and Methods Data and Formulae -
Second Edition*,
Wiley Classics Library Edition, published 2000,
ISBN-10: 0-471-39918-3,
page 141.
Examples
--------
>>> RGB_10_degree_cmfs_to_XYZ_10_degree_cmfs(700) # doctest: +ELLIPSIS
array([ 9.6432150...e-03, 3.7526317...e-03, -4.1078830...e-06])
"""
cmfs = RGB_CMFS.get('Stiles & Burch 1959 10 Degree RGB CMFs')
r_bar, g_bar, b_bar = cmfs.r_bar.get(wavelength), cmfs.g_bar.get(
wavelength), cmfs.b_bar.get(wavelength)
if None in (r_bar, g_bar, b_bar):
raise KeyError(('"{0} nm" wavelength not available in "{1}" colour '
'matching functions with "{2}" shape!').format(
wavelength, cmfs.name, cmfs.shape))
x_bar = 0.341080 * r_bar + 0.189145 * g_bar + 0.387529 * b_bar
y_bar = 0.139058 * r_bar + 0.837460 * g_bar + 0.073316 * b_bar
z_bar = 0.000000 * r_bar + 0.039553 * g_bar + 2.026200 * b_bar
return np.array([x_bar, y_bar, z_bar])
[docs]def RGB_10_degree_cmfs_to_LMS_10_degree_cmfs(wavelength):
"""
Converts *Stiles & Burch 1959 10 Degree RGB CMFs* colour matching
functions into the *Stockman & Sharpe 10 Degree Cone Fundamentals*
spectral sensitivity functions.
Parameters
----------
wavelength : numeric
Wavelength :math:`\lambda` in nm.
Returns
-------
ndarray, (3,)
*Stockman & Sharpe 10 Degree Cone Fundamentals* spectral tristimulus
values.
Raises
------
KeyError
If wavelength :math:`\lambda` is not available in the colour matching
functions.
Notes
-----
- Data for the *Stockman & Sharpe 10 Degree Cone Fundamentals* already
exists, this definition is intended for educational purpose.
References
----------
.. [3] `CIE 170-1:2006 Fundamental Chromaticity Diagram with Physiological
Axes - Part 1 <http://div1.cie.co.at/?i_ca_id=551&pubid=48>`_
Examples
--------
>>> RGB_10_degree_cmfs_to_LMS_10_degree_cmfs(700) # doctest: +ELLIPSIS
array([ 0.0052860..., 0.0003252..., 0. ])
"""
cmfs = RGB_CMFS.get('Stiles & Burch 1959 10 Degree RGB CMFs')
r_bar, g_bar, z_bar = cmfs.r_bar.get(wavelength), cmfs.g_bar.get(
wavelength), cmfs.b_bar.get(wavelength)
if None in (r_bar, g_bar, z_bar):
raise KeyError(('"{0} nm" wavelength not available in "{1}" colour '
'matching functions with "{2}" shape!').format(
wavelength, cmfs.name, cmfs.shape))
l_bar = 0.192325269 * r_bar + 0.749548882 * g_bar + 0.0675726702 * z_bar
g_bar = 0.0192290085 * r_bar + 0.940908496 * g_bar + 0.113830196 * z_bar
z_bar = (0.0105107859 * g_bar + 0.991427669 * z_bar
if wavelength <= 505 else 0)
return np.array([l_bar, g_bar, z_bar])
[docs]def LMS_2_degree_cmfs_to_XYZ_2_degree_cmfs(wavelength):
"""
Converts *Stockman & Sharpe 2 Degree Cone Fundamentals* colour matching
functions into the *CIE 2012 2 Degree Standard Observer* colour matching
functions.
Parameters
----------
wavelength : numeric
Wavelength :math:`\lambda` in nm.
Returns
-------
ndarray, (3,)
*CIE 2012 2 Degree Standard Observer* spectral tristimulus values.
Raises
------
KeyError
If wavelength :math:`\lambda` is not available in the colour matching
functions.
Notes
-----
- Data for the *CIE 2012 2 Degree Standard Observer* already exists,
this definition is intended for educational purpose.
References
----------
.. [4] http://www.cvrl.org/database/text/cienewxyz/cie2012xyz2.htm
(Last accessed 25 June 2014)
Examples
--------
>>> LMS_2_degree_cmfs_to_XYZ_2_degree_cmfs(700) # doctest: +ELLIPSIS
array([ 0.0109677..., 0.0041959..., 0. ])
"""
cmfs = LMS_CMFS.get('Stockman & Sharpe 2 Degree Cone Fundamentals')
l_bar, m_bar, s_bar = cmfs.l_bar.get(wavelength), cmfs.m_bar.get(
wavelength), cmfs.s_bar.get(wavelength)
if None in (l_bar, m_bar, s_bar):
raise KeyError(('"{0} nm" wavelength not available in "{1}" colour '
'matching functions with "{2}" shape!').format(
wavelength, cmfs.name, cmfs.shape))
x_bar = 1.94735469 * l_bar - 1.41445123 * m_bar + 0.36476327 * s_bar
y_bar = 0.68990272 * l_bar + 0.34832189 * m_bar
z_bar = 1.93485343 * s_bar
return np.array([x_bar, y_bar, z_bar])
def LMS_10_degree_cmfs_to_XYZ_10_degree_cmfs(wavelength):
"""
Converts *Stockman & Sharpe 10 Degree Cone Fundamentals* colour matching
functions into the *CIE 2012 10 Degree Standard Observer* colour matching
functions.
Parameters
----------
wavelength : numeric
Wavelength :math:`\lambda` in nm.
Returns
-------
ndarray, (3,)
*CIE 2012 10 Degree Standard Observer* spectral tristimulus values.
Raises
------
KeyError
If wavelength :math:`\lambda` is not available in the colour matching
functions.
Notes
-----
- Data for the *CIE 2012 10 Degree Standard Observer* already exists,
this definition is intended for educational purpose.
References
----------
.. [5] http://www.cvrl.org/database/text/cienewxyz/cie2012xyz10.htm
(Last accessed 25 June 2014)
Examples
--------
>>> LMS_10_degree_cmfs_to_XYZ_10_degree_cmfs(700) # doctest: +ELLIPSIS
array([ 0.0098162..., 0.0037761..., 0. ])
"""
cmfs = LMS_CMFS.get('Stockman & Sharpe 10 Degree Cone Fundamentals')
l_bar, m_bar, s_bar = cmfs.l_bar.get(wavelength), cmfs.m_bar.get(
wavelength), cmfs.s_bar.get(wavelength)
if None in (l_bar, m_bar, s_bar):
raise KeyError(('"{0} nm" wavelength not available in "{1}" colour '
'matching functions with "{2}" shape!').format(
wavelength, cmfs.name, cmfs.shape))
x_bar = 1.93986443 * l_bar - 1.34664359 * m_bar + 0.43044935 * s_bar
y_bar = 0.69283932 * l_bar + 0.34967567 * m_bar
z_bar = 2.14687945 * s_bar
return np.array([x_bar, y_bar, z_bar])
Colour 0.3