#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
RGB Colourspace & Transformations
=================================
Defines the :class:`RGB_Colourspace` class for the *RGB* colourspaces dataset
from :mod:`colour.models.dataset.aces_rgb`, etc... and the following *RGB*
colourspace transformations:
- :func:`XYZ_to_RGB`
- :func:`RGB_to_XYZ`
- :func:`RGB_to_RGB`
See Also
--------
`RGB Colourspaces IPython Notebook
<http://nbviewer.ipython.org/github/colour-science/colour-ipython/blob/master/notebooks/models/rgb.ipynb>`_ # noqa
"""
from __future__ import division, unicode_literals
import numpy as np
from colour.models import xy_to_XYZ, xy_to_xyY, xyY_to_XYZ
from colour.adaptation import chromatic_adaptation_matrix_VonKries
from colour.utilities import dot_matrix, dot_vector
__author__ = 'Colour Developers'
__copyright__ = 'Copyright (C) 2013 - 2015 - 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_Colourspace',
'XYZ_to_RGB',
'RGB_to_XYZ',
'RGB_to_RGB']
[docs]class RGB_Colourspace(object):
"""
Implements support for the *RGB* colourspaces dataset from
:mod:`colour.models.dataset.aces_rgb`, etc....
Parameters
----------
name : unicode
*RGB* colourspace name.
primaries : array_like
*RGB* colourspace primaries.
whitepoint : array_like
*RGB* colourspace whitepoint.
illuminant : unicode, optional
*RGB* colourspace whitepoint name as illuminant.
RGB_to_XYZ_matrix : array_like, optional
Transformation matrix from colourspace to *CIE XYZ* tristimulus values.
XYZ_to_RGB_matrix : array_like, optional
Transformation matrix from *CIE XYZ* tristimulus values to colourspace.
transfer_function : object, optional
*RGB* colourspace opto-electronic conversion function from linear to
colourspace.
inverse_transfer_function : object, optional
*RGB* colourspace inverse opto-electronic conversion function from
colourspace to linear.
"""
def __init__(self,
name,
primaries,
whitepoint,
illuminant=None,
RGB_to_XYZ_matrix=None,
XYZ_to_RGB_matrix=None,
transfer_function=None,
inverse_transfer_function=None):
self.__name = None
self.name = name
self.__primaries = None
self.primaries = primaries
self.__whitepoint = None
self.whitepoint = whitepoint
self.__illuminant = None
self.illuminant = illuminant
self.__RGB_to_XYZ_matrix = None
self.RGB_to_XYZ_matrix = RGB_to_XYZ_matrix
self.__XYZ_to_RGB_matrix = None
self.XYZ_to_RGB_matrix = XYZ_to_RGB_matrix
self.__transfer_function = None
self.transfer_function = transfer_function
self.__inverse_transfer_function = None
self.inverse_transfer_function = inverse_transfer_function
@property
def name(self):
"""
Property for **self.__name** private attribute.
Returns
-------
unicode
self.__name.
"""
return self.__name
@name.setter
[docs] def name(self, value):
"""
Setter for **self.__name** private attribute.
Parameters
----------
value : unicode
Attribute value.
"""
if value is not None:
assert type(value) in (str, unicode), ( # noqa
('"{0}" attribute: "{1}" type is not '
'"str" or "unicode"!').format('name', value))
self.__name = value
@property
def primaries(self):
"""
Property for **self.__primaries** private attribute.
Returns
-------
array_like, (3, 2)
self.__primaries.
"""
return self.__primaries
@primaries.setter
[docs] def primaries(self, value):
"""
Setter for **self.__primaries** private attribute.
Parameters
----------
value : array_like, (3, 2)
Attribute value.
"""
if value is not None:
value = np.asarray(value)
self.__primaries = value
@property
def whitepoint(self):
"""
Property for **self.__whitepoint** private attribute.
Returns
-------
array_like
self.__whitepoint.
"""
return self.__whitepoint
@whitepoint.setter
[docs] def whitepoint(self, value):
"""
Setter for **self.__whitepoint** private attribute.
Parameters
----------
value : array_like
Attribute value.
"""
if value is not None:
assert type(value) in (tuple, list, np.ndarray, np.matrix), (
('"{0}" attribute: "{1}" type is not "tuple", "list", '
'"ndarray" or "matrix"!').format('whitepoint', value))
self.__whitepoint = value
@property
def illuminant(self):
"""
Property for **self.__illuminant** private attribute.
Returns
-------
unicode
self.__illuminant.
"""
return self.__illuminant
@illuminant.setter
[docs] def illuminant(self, value):
"""
Setter for **self.__illuminant** private attribute.
Parameters
----------
value : unicode
Attribute value.
"""
if value is not None:
assert type(value) in (str, unicode), ( # noqa
('"{0}" attribute: "{1}" type is not '
'"str" or "unicode"!').format('illuminant', value))
self.__illuminant = value
@property
def RGB_to_XYZ_matrix(self):
"""
Property for **self.__to_XYZ** private attribute.
Returns
-------
array_like, (3, 3)
self.__to_XYZ.
"""
return self.__RGB_to_XYZ_matrix
@RGB_to_XYZ_matrix.setter
[docs] def RGB_to_XYZ_matrix(self, value):
"""
Setter for **self.__to_XYZ** private attribute.
Parameters
----------
value : array_like
Attribute value.
"""
if value is not None:
value = np.asarray(value)
self.__RGB_to_XYZ_matrix = value
@property
def XYZ_to_RGB_matrix(self):
"""
Property for **self.__to_RGB** private attribute.
Returns
-------
array_like, (3, 3)
self.__to_RGB.
"""
return self.__XYZ_to_RGB_matrix
@XYZ_to_RGB_matrix.setter
[docs] def XYZ_to_RGB_matrix(self, value):
"""
Setter for **self.__to_RGB** private attribute.
Parameters
----------
value : array_like
Attribute value.
"""
if value is not None:
value = np.asarray(value)
self.__XYZ_to_RGB_matrix = value
@property
def transfer_function(self):
"""
Property for **self.__transfer_function** private attribute.
Returns
-------
object
self.__transfer_function.
"""
return self.__transfer_function
@transfer_function.setter
[docs] def transfer_function(self, value):
"""
Setter for **self.__transfer_function** private attribute.
Parameters
----------
value : object
Attribute value.
"""
if value is not None:
assert hasattr(value, '__call__'), (
'"{0}" attribute: "{1}" is not callable!'.format(
'transfer_function', value))
self.__transfer_function = value
@property
def inverse_transfer_function(self):
"""
Property for **self.__inverse_transfer_function** private attribute.
Returns
-------
object
self.__inverse_transfer_function.
"""
return self.__inverse_transfer_function
@inverse_transfer_function.setter
[docs] def inverse_transfer_function(self, value):
"""
Setter for **self.__inverse_transfer_function** private attribute.
Parameters
----------
value : object
Attribute value.
"""
if value is not None:
assert hasattr(value, '__call__'), (
'"{0}" attribute: "{1}" is not callable!'.format(
'inverse_transfer_function', value))
self.__inverse_transfer_function = value
[docs]def XYZ_to_RGB(XYZ,
illuminant_XYZ,
illuminant_RGB,
XYZ_to_RGB_matrix,
chromatic_adaptation_transform='CAT02',
transfer_function=None):
"""
Converts from *CIE XYZ* tristimulus values to given *RGB* colourspace.
Parameters
----------
XYZ : array_like
*CIE XYZ* tristimulus values.
illuminant_XYZ : array_like
*CIE XYZ* tristimulus values *illuminant* *xy* chromaticity coordinates
or *CIE xyY* colourspace array.
illuminant_RGB : array_like
*RGB* colourspace *illuminant* *xy* chromaticity coordinates or
*CIE xyY* colourspace array.
XYZ_to_RGB_matrix : array_like
*Normalised primary matrix*.
chromatic_adaptation_transform : unicode, optional
**{'CAT02', 'XYZ Scaling', 'Von Kries', 'Bradford', 'Sharp',
'Fairchild, 'CMCCAT97', 'CMCCAT2000', 'CAT02_BRILL_CAT', 'Bianco',
'Bianco PC'}**,
*Chromatic adaptation* transform.
transfer_function : object, optional
*Transfer function*.
Returns
-------
ndarray
*RGB* colourspace array.
Notes
-----
- Input *CIE XYZ* tristimulus values are in domain [0, 1].
- Input *illuminant_XYZ* *xy* chromaticity coordinates or *CIE xyY*
colourspace array are in domain [0, :math:`\infty`].
- Input *illuminant_RGB* *xy* chromaticity coordinates or *CIE xyY*
colourspace array are in domain [0, :math:`\infty`].
- Output *RGB* colourspace array is in domain [0, 1].
Examples
--------
>>> XYZ = np.array([0.07049534, 0.10080000, 0.09558313])
>>> illuminant_XYZ = np.array([0.34567, 0.35850])
>>> illuminant_RGB = np.array([0.31271, 0.32902])
>>> chromatic_adaptation_transform = 'Bradford'
>>> XYZ_to_RGB_matrix = np.array([
... [3.24100326, -1.53739899, -0.49861587],
... [-0.96922426, 1.87592999, 0.04155422],
... [0.05563942, -0.20401120, 1.05714897]])
>>> XYZ_to_RGB(
... XYZ,
... illuminant_XYZ,
... illuminant_RGB,
... XYZ_to_RGB_matrix,
... chromatic_adaptation_transform) # doctest: +ELLIPSIS
array([ 0.0110360..., 0.1273446..., 0.1163103...])
"""
M = chromatic_adaptation_matrix_VonKries(
xyY_to_XYZ(xy_to_xyY(illuminant_XYZ)),
xyY_to_XYZ(xy_to_xyY(illuminant_RGB)),
transform=chromatic_adaptation_transform)
XYZ_a = dot_vector(M, XYZ)
RGB = dot_vector(XYZ_to_RGB_matrix, XYZ_a)
if transfer_function is not None:
RGB = transfer_function(RGB)
return RGB
[docs]def RGB_to_XYZ(RGB,
illuminant_RGB,
illuminant_XYZ,
RGB_to_XYZ_matrix,
chromatic_adaptation_transform='CAT02',
inverse_transfer_function=None):
"""
Converts from given *RGB* colourspace to *CIE XYZ* tristimulus values.
Parameters
----------
RGB : array_like
*RGB* colourspace array.
illuminant_RGB : array_like
*RGB* colourspace *illuminant* chromaticity coordinates or *CIE xyY*
colourspace array.
illuminant_XYZ : array_like
*CIE XYZ* tristimulus values *illuminant* chromaticity coordinates or
*CIE xyY* colourspace array.
RGB_to_XYZ_matrix : array_like
*Normalised primary matrix*.
chromatic_adaptation_transform : unicode, optional
**{'CAT02', 'XYZ Scaling', 'Von Kries', 'Bradford', 'Sharp',
'Fairchild, 'CMCCAT97', 'CMCCAT2000', 'CAT02_BRILL_CAT', 'Bianco',
'Bianco PC'}**,
*Chromatic adaptation* transform.
inverse_transfer_function : object, optional
*Inverse transfer function*.
Returns
-------
ndarray
*CIE XYZ* tristimulus values.
Notes
-----
- Input *RGB* colourspace array is in domain [0, 1].
- Input *illuminant_RGB* *xy* chromaticity coordinates or *CIE xyY*
colourspace array are in domain [0, :math:`\infty`].
- Input *illuminant_XYZ* *xy* chromaticity coordinates or *CIE xyY*
colourspace array are in domain [0, :math:`\infty`].
- Output *CIE XYZ* tristimulus values are in domain [0, 1].
Examples
--------
>>> RGB = np.array([0.01103604, 0.12734466, 0.11631037])
>>> illuminant_RGB = np.array([0.31271, 0.32902])
>>> illuminant_XYZ = np.array([0.34567, 0.35850])
>>> chromatic_adaptation_transform = 'Bradford'
>>> RGB_to_XYZ_matrix = np.array([
... [0.41238656, 0.35759149, 0.18045049],
... [0.21263682, 0.71518298, 0.07218020],
... [0.01933062, 0.11919716, 0.95037259]])
>>> RGB_to_XYZ(
... RGB,
... illuminant_RGB,
... illuminant_XYZ,
... RGB_to_XYZ_matrix,
... chromatic_adaptation_transform) # doctest: +ELLIPSIS
array([ 0.0704953..., 0.1008 , 0.0955831...])
"""
if inverse_transfer_function is not None:
RGB = inverse_transfer_function(RGB)
M = chromatic_adaptation_matrix_VonKries(
xyY_to_XYZ(xy_to_xyY(illuminant_RGB)),
xyY_to_XYZ(xy_to_xyY(illuminant_XYZ)),
transform=chromatic_adaptation_transform)
XYZ = dot_vector(RGB_to_XYZ_matrix, RGB)
XYZ_a = dot_vector(M, XYZ)
return XYZ_a
[docs]def RGB_to_RGB(RGB,
input_colourspace,
output_colourspace,
chromatic_adaptation_transform='CAT02'):
"""
Converts from given input *RGB* colourspace to output *RGB* colourspace
using given *chromatic adaptation* method.
Parameters
----------
RGB : array_like
*RGB* colourspace array.
input_colourspace : RGB_Colourspace
*RGB* input colourspace.
output_colourspace : RGB_Colourspace
*RGB* output colourspace.
chromatic_adaptation_transform : unicode, optional
**{'CAT02', 'XYZ Scaling', 'Von Kries', 'Bradford', 'Sharp',
'Fairchild, 'CMCCAT97', 'CMCCAT2000', 'CAT02_BRILL_CAT', 'Bianco',
'Bianco PC'}**,
*Chromatic adaptation* transform.
ndarray
*RGB* colourspace array.
Notes
-----
- *RGB* colourspace arrays are in domain [0, 1].
Examples
--------
>>> from colour import sRGB_COLOURSPACE, PROPHOTO_RGB_COLOURSPACE
>>> RGB = np.array([0.01103604, 0.12734466, 0.11631037])
>>> RGB_to_RGB(
... RGB,
... sRGB_COLOURSPACE,
... PROPHOTO_RGB_COLOURSPACE) # doctest: +ELLIPSIS
array([ 0.0643338..., 0.1157362..., 0.1157614...])
"""
cat = chromatic_adaptation_matrix_VonKries(
xy_to_XYZ(input_colourspace.whitepoint),
xy_to_XYZ(output_colourspace.whitepoint),
chromatic_adaptation_transform)
M = dot_matrix(cat, input_colourspace.RGB_to_XYZ_matrix)
M = dot_matrix(output_colourspace.XYZ_to_RGB_matrix, M)
RGB = dot_vector(M, RGB)
return RGB
Colour 0.3