def _rec_709_EOCF(value):
"""
Defines the *Rec. 709* colourspace electro-optical conversion function.
Parameters
----------
value : numeric or array_like
Value.
Returns
-------
numeric or ndarray
Companded value.
Warning
-------
*Recommendation ITU-R BT.709-5* doesn't specify an electro-optical
conversion function. This definition is used for symmetry in unit tests and
other computations but should not be used as an *EOCF* for *Rec. 709*
colourspace!
"""
warning(('*Recommendation ITU-R BT.709-5* doesn\'t specify an'
'electro-optical conversion function. This definition is used '
'for symmetry in unit tests and others computations but should '
'not be used as an *EOCF* for *Rec. 709* colourspace!'))
value = np.asarray(value)
return np.where(value < _rec_709_OECF(0.018), value / 4.5,
((value + 0.099) / 1.099)**(1 / 0.45))
def test_suppress_warnings(self):
"""
Tests :func:`colour.utilities.verbose.suppress_warnings` definition.
"""
with suppress_warnings():
warning('This is a suppressed unit test warning!')
def x(self, value):
"""
Setter for the **self.x** property.
"""
if value is not None:
value = np.atleast_1d(value).astype(self._dtype)
assert value.ndim == 1, (
'"x" independent variable must have exactly one dimension!')
value_interval = interval(value)
if value_interval.size != 1:
warning(('"x" independent variable is not uniform, '
'unpredictable results may occur!'))
self._x = value
if self._window is not None:
self._x_p = np.pad(
self._x, (self._window, self._window),
'linear_ramp',
end_values=(
np.min(self._x) - self._window * value_interval[0],
np.max(self._x) + self._window * value_interval[0]))
def eotf_sRGB(V):
"""
Defines the *sRGB* colourspace electro-optical transfer function
(EOTF / EOCF).
Parameters
----------
V : numeric or array_like
Electrical signal :math:`V`.
Returns
-------
numeric or ndarray
Corresponding *luminance* :math:`L` of the image.
Examples
--------
>>> eotf_sRGB(0.461356129500442) # doctest: +ELLIPSIS
0.1...
"""
warning(('*sRGB* *OETF* is a piece-wise function: in order to reduce '
'noise in dark region, a line segment limits the slope of the '
'power function (slope of a power function is infinite at zero). '
'This is not needed for *sRGB* *EOTF*, a pure gamma 2.2 function '
'should be use instead. This definition is used for symmetry in '
'unit tests and others computations but should not be used as an '
'*EOTF*!'))
V = np.asarray(V)
return as_numeric(
np.where(V <= oetf_sRGB(0.0031308), V / 12.92,
((V + 0.055) / 1.055)**2.4))
def _rec_709_EOCF(value):
"""
Defines the *Rec. 709* colourspace electro-optical conversion function.
Parameters
----------
value : numeric or array_like
Value.
Returns
-------
numeric or ndarray
Companded value.
Warning
-------
*Recommendation ITU-R BT.709-5* doesn't specify an electro-optical
conversion function. This definition is used for symmetry in unit tests and
other computations but should not be used as an *EOCF* for *Rec. 709*
colourspace!
"""
warning(
(
"*Recommendation ITU-R BT.709-5* doesn't specify an"
"electro-optical conversion function. This definition is used "
"for symmetry in unit tests and others computations but should "
"not be used as an *EOCF* for *Rec. 709* colourspace!"
)
)
value = np.asarray(value)
return np.where(value < _rec_709_OECF(0.018), value / 4.5, ((value + 0.099) / 1.099) ** (1 / 0.45))
def __getattr__(self, attribute):
"""
Returns given attribute value while handling deprecation.
Parameters
----------
attribute : unicode
Attribute name.
Returns
-------
object
Attribute value.
Raises
------
AttributeError
If the attribute is not defined.
"""
change = self._changes.get(attribute)
if change is not None:
if not isinstance(change, Removed):
warning(str(change))
return get_attribute(change[1])
else:
raise AttributeError(str(change))
return getattr(self._module, attribute)
def random_triplet_generator(size,
limits=np.array([[0, 1], [0, 1], [0, 1]]),
random_state=RANDOM_STATE):
"""
Returns a generator yielding random triplets.
Parameters
----------
size : integer
Generator size.
limits : array_like, (3, 2)
Random values limits on each triplet axis.
random_state : RandomState
Mersenne Twister pseudo-random number generator.
Returns
-------
generator
Random triplets generator.
Notes
-----
The doctest is assuming that :func:`np.random.RandomState` definition will
return the same sequence no matter which *OS* or *Python* version is used.
There is however no formal promise about the *prng* sequence
reproducibility of either *Python* or *Numpy* implementations: Laurent.
(2012). Reproducibility of python pseudo-random numbers across systems and
versions? Retrieved January 20, 2015, from http://stackoverflow.com/\
questions/8786084/reproducibility-of-python-pseudo-random-numbers-\
across-systems-and-versions
Examples
--------
>>> from pprint import pprint
>>> prng = np.random.RandomState(4)
>>> pprint( # doctest: +ELLIPSIS
... tuple(random_triplet_generator(10, random_state=prng)))
(array([ 0.9670298..., 0.5472322..., 0.9726843...]),
array([ 0.7148159..., 0.6977288..., 0.2160895...]),
array([ 0.9762744..., 0.0062302..., 0.2529823...]),
array([ 0.4347915..., 0.7793829..., 0.1976850...]),
array([ 0.8629932..., 0.9834006..., 0.1638422...]),
array([ 0.5973339..., 0.0089861..., 0.3865712...]),
array([ 0.0441600..., 0.9566529..., 0.4361466...]),
array([ 0.9489773..., 0.7863059..., 0.8662893...]),
array([ 0.1731654..., 0.0749485..., 0.6007427...]),
array([ 0.1679721..., 0.7333801..., 0.4084438...]))
"""
integer_size = int(size)
if integer_size != size:
warning(('"size" has been cast to integer: {0}'.format(integer_size)))
for _ in range(integer_size):
yield np.array([
random_state.uniform(*limits[0]),
random_state.uniform(*limits[1]),
random_state.uniform(*limits[2])
])
def random_triplet_generator(size,
limits=np.array([[0, 1], [0, 1], [0, 1]]),
random_state=RANDOM_STATE):
"""
Returns a generator yielding random triplets.
Parameters
----------
size : integer
Generator size.
limits : array_like, (3, 2)
Random values limits on each triplet axis.
random_state : RandomState
Mersenne Twister pseudo-random number generator.
Returns
-------
generator
Random triplets generator.
Notes
-----
The doctest is assuming that :func:`np.random.RandomState` definition will
return the same sequence no matter which *OS* or *Python* version is used.
There is however no formal promise about the *prng* sequence
reproducibility of either *Python* or *Numpy* implementations: Laurent.
(2012). Reproducibility of python pseudo-random numbers across systems and
versions? Retrieved January 20, 2015, from http://stackoverflow.com/\
questions/8786084/reproducibility-of-python-pseudo-random-numbers-\
across-systems-and-versions
Examples
--------
>>> from pprint import pprint
>>> prng = np.random.RandomState(4)
>>> pprint( # doctest: +ELLIPSIS
... tuple(random_triplet_generator(10, random_state=prng)))
(array([ 0.9670298..., 0.5472322..., 0.9726843...]),
array([ 0.7148159..., 0.6977288..., 0.2160895...]),
array([ 0.9762744..., 0.0062302..., 0.2529823...]),
array([ 0.4347915..., 0.7793829..., 0.1976850...]),
array([ 0.8629932..., 0.9834006..., 0.1638422...]),
array([ 0.5973339..., 0.0089861..., 0.3865712...]),
array([ 0.0441600..., 0.9566529..., 0.4361466...]),
array([ 0.9489773..., 0.7863059..., 0.8662893...]),
array([ 0.1731654..., 0.0749485..., 0.6007427...]),
array([ 0.1679721..., 0.7333801..., 0.4084438...]))
"""
integer_size = int(size)
if integer_size != size:
warning(('"size" has been cast to integer: {0}'.format(
integer_size)))
for _ in range(integer_size):
yield np.array([random_state.uniform(*limits[0]),
random_state.uniform(*limits[1]),
random_state.uniform(*limits[2])])
def CCT_to_xy_Kang2002(CCT):
"""
Returns the *CIE XYZ* tristimulus values *xy* chromaticity coordinates from
given correlated colour temperature :math:`T_{cp}` using Kang et al. (2002)
method.
Parameters
----------
CCT : numeric or array_like
Correlated colour temperature :math:`T_{cp}`.
Returns
-------
ndarray
*xy* chromaticity coordinates.
Raises
------
ValueError
If the correlated colour temperature is not in appropriate domain.
References
----------
.. [11] Kang, B., Moon, O., Hong, C., Lee, H., Cho, B., & Kim, Y. (2002).
Design of advanced color: Temperature control system for HDTV
applications. Journal of the Korean …, 41(6), 865–871. Retrieved
from http://cat.inist.fr/?aModele=afficheN&cpsidt=14448733
Examples
--------
>>> CCT_to_xy_Kang2002(6504.38938305) # doctest: +ELLIPSIS
array([ 0.313426..., 0.3235959...])
"""
CCT = np.asarray(CCT)
if np.any(CCT[np.asarray(np.logical_or(CCT < 1667, CCT > 25000))]):
warning(('Correlated colour temperature must be in domain '
'[1667, 25000], unpredictable results may occur!'))
x = np.where(
CCT <= 4000, -0.2661239 * 10**9 / CCT**3 - 0.2343589 * 10**6 / CCT**2 +
0.8776956 * 10**3 / CCT + 0.179910, -3.0258469 * 10**9 / CCT**3 +
2.1070379 * 10**6 / CCT**2 + 0.2226347 * 10**3 / CCT + 0.24039)
y = np.select([
CCT <= 2222,
np.logical_and(CCT > 2222, CCT <= 4000), CCT > 4000
], [
-1.1063814 * x**3 - 1.34811020 * x**2 + 2.18555832 * x - 0.20219683,
-0.9549476 * x**3 - 1.37418593 * x**2 + 2.09137015 * x - 0.16748867,
3.0817580 * x**3 - 5.8733867 * x**2 + 3.75112997 * x - 0.37001483
])
xy = tstack((x, y))
return xy
def CCT_to_xy_CIE_D(CCT):
"""
Converts from the correlated colour temperature :math:`T_{cp}` of a
*CIE Illuminant D Series* to the chromaticity of that
*CIE Illuminant D Series* illuminant.
Parameters
----------
CCT : numeric or array_like
Correlated colour temperature :math:`T_{cp}`.
Returns
-------
ndarray
*xy* chromaticity coordinates.
Raises
------
ValueError
If the correlated colour temperature is not in appropriate domain.
References
----------
.. [12] Wyszecki, G., & Stiles, W. S. (2000). CIE Method of Calculating
D-Illuminants. In Color Science: Concepts and Methods,
Quantitative Data and Formulae (pp. 145–146). Wiley.
ISBN:978-0471399186
Examples
--------
>>> CCT_to_xy_CIE_D(6504.38938305) # doctest: +ELLIPSIS
array([ 0.3127077..., 0.3291128...])
"""
CCT = np.asarray(CCT)
if np.any(CCT[np.asarray(np.logical_or(CCT < 4000, CCT > 25000))]):
warning(('Correlated colour temperature must be in domain '
'[4000, 25000], unpredictable results may occur!'))
x = np.where(CCT <= 7000,
-4.607 * 10 ** 9 / CCT ** 3 +
2.9678 * 10 ** 6 / CCT ** 2 +
0.09911 * 10 ** 3 / CCT +
0.244063,
-2.0064 * 10 ** 9 / CCT ** 3 +
1.9018 * 10 ** 6 / CCT ** 2 +
0.24748 * 10 ** 3 / CCT +
0.23704)
y = -3 * x ** 2 + 2.87 * x - 0.275
xy = tstack((x, y))
return xy
def CCT_to_xy_CIE_D(CCT):
"""
Converts from the correlated colour temperature :math:`T_{cp}` of a
*CIE Illuminant D Series* to the chromaticity of that
*CIE Illuminant D Series* illuminant.
Parameters
----------
CCT : numeric or array_like
Correlated colour temperature :math:`T_{cp}`.
Returns
-------
ndarray
*xy* chromaticity coordinates.
Raises
------
ValueError
If the correlated colour temperature is not in appropriate domain.
References
----------
.. [12] Wyszecki, G., & Stiles, W. S. (2000). CIE Method of Calculating
D-Illuminants. In Color Science: Concepts and Methods,
Quantitative Data and Formulae (pp. 145–146). Wiley.
ISBN:978-0471399186
Examples
--------
>>> CCT_to_xy_CIE_D(6504.38938305) # doctest: +ELLIPSIS
array([ 0.3127077..., 0.3291128...])
"""
CCT = np.asarray(CCT)
if np.any(CCT[np.asarray(np.logical_or(CCT < 4000, CCT > 25000))]):
warning(('Correlated colour temperature must be in domain '
'[4000, 25000], unpredictable results may occur!'))
x = np.where(CCT <= 7000,
-4.607 * 10 ** 9 / CCT ** 3 +
2.9678 * 10 ** 6 / CCT ** 2 +
0.09911 * 10 ** 3 / CCT +
0.244063,
-2.0064 * 10 ** 9 / CCT ** 3 +
1.9018 * 10 ** 6 / CCT ** 2 +
0.24748 * 10 ** 3 / CCT +
0.23704)
y = -3 * x ** 2 + 2.87 * x - 0.275
xy = tstack((x, y))
return xy
def read_metadata(self):
"""
Reads image relevant exif metadata at :attr:`Image.path` attribute.
Returns
-------
Metadata
Image relevant exif metadata.
"""
logging.info('Reading "{0}" image metadata.'.format(self._path))
exif_data = read_exif_tags(self._path)
if not exif_data.get('EXIF'):
warning(
'"{0}" file has no "Exif" data, metadata will be undefined!'.
format(self._path))
self.metadata = Metadata(*[None] * 6)
return self.metadata
f_number = exif_data['EXIF'].get('F Number')
if f_number is not None:
f_number = parse_exif_numeric(f_number[0])
exposure_time = exif_data['EXIF'].get('Exposure Time')
if exposure_time is not None:
exposure_time = parse_exif_fraction(exposure_time[0])
iso = exif_data['EXIF'].get('ISO')
if iso is not None:
iso = parse_exif_numeric(iso[0])
black_level = exif_data['EXIF'].get('Black Level')
if black_level is not None:
black_level = parse_exif_array(black_level[0])
black_level = as_float_array(black_level) / 65535
white_level = exif_data['EXIF'].get('White Level')
if white_level is not None:
white_level = parse_exif_array(white_level[0])
white_level = as_float_array(white_level) / 65535
white_balance_multipliers = exif_data['EXIF'].get('As Shot Neutral')
if white_balance_multipliers is not None:
white_balance_multipliers = parse_exif_array(
white_balance_multipliers[0])
white_balance_multipliers = as_float_array(
white_balance_multipliers) / white_balance_multipliers[1]
self.metadata = Metadata(f_number, exposure_time, iso, black_level,
white_level, white_balance_multipliers)
return self.metadata
def CCT_to_xy_Kang2002(CCT):
"""
Returns the *CIE XYZ* tristimulus values *xy* chromaticity coordinates from
given correlated colour temperature :math:`T_{cp}` using
*Kang et alii (2002)* method.
Parameters
----------
CCT : numeric or array_like
Correlated colour temperature :math:`T_{cp}`.
Returns
-------
ndarray
*xy* chromaticity coordinates.
Raises
------
ValueError
If the correlated colour temperature is not in appropriate domain.
References
----------
- :cite:`Kang2002a`
Examples
--------
>>> CCT_to_xy_Kang2002(6504.38938305) # doctest: +ELLIPSIS
array([ 0.313426..., 0.3235959...])
"""
CCT = np.asarray(CCT)
if np.any(CCT[np.asarray(np.logical_or(CCT < 1667, CCT > 25000))]):
warning(('Correlated colour temperature must be in domain '
'[1667, 25000], unpredictable results may occur!'))
x = np.where(
CCT <= 4000, -0.2661239 * 10 ** 9 / CCT ** 3 -
0.2343589 * 10 ** 6 / CCT ** 2 + 0.8776956 * 10 ** 3 / CCT + 0.179910,
-3.0258469 * 10 ** 9 / CCT ** 3 + 2.1070379 * 10 ** 6 / CCT ** 2 +
0.2226347 * 10 ** 3 / CCT + 0.24039)
cnd_l = [CCT <= 2222, np.logical_and(CCT > 2222, CCT <= 4000), CCT > 4000]
i = -1.1063814 * x ** 3 - 1.34811020 * x ** 2 + 2.18555832 * x - 0.20219683
j = -0.9549476 * x ** 3 - 1.37418593 * x ** 2 + 2.09137015 * x - 0.16748867
k = 3.0817580 * x ** 3 - 5.8733867 * x ** 2 + 3.75112997 * x - 0.37001483
y = np.select(cnd_l, [i, j, k])
xy = tstack((x, y))
return xy
def light_probe_sampling_variance_minimization_Viriyothai2009(
light_probe, lights_count=16, colourspace=RGB_COLOURSPACES['sRGB']):
"""
Sample given light probe to find lights using *Viriyothai (2009)* variance
minimization light probe sampling algorithm.
Parameters
----------
light_probe : array_like
Array to sample for lights.
lights_count : int
Amount of lights to generate.
colourspace : `colour.RGB_Colourspace`, optional
*RGB* colourspace used for internal *Luminance* computation.
Returns
-------
list
list of
:class:`colour_hdri.sampling.variance_minimization.Light_Specification`
lights.
References
----------
:cite:`Viriyothai2009`
"""
light_probe = as_float_array(light_probe)
iterations = np.sqrt(lights_count).astype(np.int_)
if iterations**2 != lights_count:
warning(
'{0} lights requested, {1} will be effectively computed!'.format(
lights_count, iterations**2))
Y = RGB_luminance(light_probe, colourspace.primaries,
colourspace.whitepoint)
regions = find_regions_variance_minimization_Viriyothai2009(Y, iterations)
lights = []
for region in regions:
y_min, y_max, x_min, x_max = region
c = centroid(Y[y_min:y_max, x_min:x_max])
c = (c + np.array([y_min, x_min]))
light_probe_c = light_probe[y_min:y_max, x_min:x_max]
lights.append(
Light_Specification((c / np.array(Y.shape))[::-1],
np.sum(np.sum(light_probe_c, 0), 0), c))
return lights
def oetf_BT1886(L, L_B=64, L_W=940):
"""
Defines *Recommendation ITU-R BT.1886* opto-electrical transfer function
(OETF / OECF).
Parameters
----------
L : numeric or array_like
Screen luminance in :math:`cd/m^2`.
L_B : numeric, optional
Screen luminance for black.
L_W : numeric, optional
Screen luminance for white.
Returns
-------
numeric or ndarray
Input video signal level (normalized, black at :math:`V = 0`, to white
at :math:`V = 1`.
Warning
-------
*Recommendation ITU-R BT.1886* doesn't specify an opto-electrical
transfer function. This definition is used for symmetry in unit tests and
other computations but should not be used as an *OETF*.
Examples
--------
>>> oetf_BT1886(277.98159179331145) # doctest: +ELLIPSIS
0.4090077...
"""
warning(('*Recommendation ITU-R BT.1886* doesn\'t specify an '
'opto-electrical transfer function. This definition is used '
'for symmetry in unit tests and others computations but should '
'not be used as an *OETF*!'))
L = np.asarray(L)
gamma = 2.40
gamma_d = 1 / gamma
n = L_W ** gamma_d - L_B ** gamma_d
a = n ** gamma
b = L_B ** gamma_d / n
V = (L / a) ** gamma_d - b
return V
def oetf_BT1886(L, L_B=0, L_W=1):
"""
Defines *Recommendation ITU-R BT.1886* opto-electrical transfer function
(OETF / OECF).
Parameters
----------
L : numeric or array_like
Screen luminance in :math:`cd/m^2`.
L_B : numeric, optional
Screen luminance for black.
L_W : numeric, optional
Screen luminance for white.
Returns
-------
numeric or ndarray
Input video signal level (normalized, black at :math:`V = 0`, to white
at :math:`V = 1`.
Warning
-------
*Recommendation ITU-R BT.1886* doesn't specify an opto-electrical
transfer function. This definition is used for symmetry in unit tests and
other computations but should not be used as an *OETF*.
Examples
--------
>>> oetf_BT1886(0.11699185725296059) # doctest: +ELLIPSIS
0.4090077...
"""
warning(('*Recommendation ITU-R BT.1886* doesn\'t specify an '
'opto-electrical transfer function. This definition is used '
'for symmetry in unit tests and others computations but should '
'not be used as an *OETF*!'))
L = np.asarray(L)
gamma = 2.40
gamma_d = 1 / gamma
n = L_W**gamma_d - L_B**gamma_d
a = n**gamma
b = L_B**gamma_d / n
V = (L / a)**gamma_d - b
return V
def luminance_average_key(image):
"""
Comparison key function.
"""
f_number = image.metadata.f_number
exposure_time = image.metadata.exposure_time
iso = image.metadata.iso
if None in (f_number, exposure_time, iso):
warning('"{0}" exposure data is missing, average luminance '
'sorting is inapplicable!'.format(image.path))
return None
return 1 / average_luminance(f_number, exposure_time, iso)
def CCT_to_xy_CIE_D(CCT):
"""
Converts from the correlated colour temperature :math:`T_{cp}` of a
*CIE Illuminant D Series* to the chromaticity of that
*CIE Illuminant D Series* illuminant.
Parameters
----------
CCT : numeric or array_like
Correlated colour temperature :math:`T_{cp}`.
Returns
-------
ndarray
*xy* chromaticity coordinates.
Raises
------
ValueError
If the correlated colour temperature is not in appropriate domain.
References
----------
- :cite:`Wyszecki2000z`
Examples
--------
>>> CCT_to_xy_CIE_D(6504.38938305) # doctest: +ELLIPSIS
array([ 0.3127077..., 0.3291128...])
"""
CCT = np.asarray(CCT)
if np.any(CCT[np.asarray(np.logical_or(CCT < 4000, CCT > 25000))]):
warning(('Correlated colour temperature must be in domain '
'[4000, 25000], unpredictable results may occur!'))
x = np.where(
CCT <= 7000, -4.607 * 10 ** 9 / CCT ** 3 + 2.9678 * 10 ** 6 / CCT ** 2
+ 0.09911 * 10 ** 3 / CCT + 0.244063, -2.0064 * 10 ** 9 / CCT ** 3 +
1.9018 * 10 ** 6 / CCT ** 2 + 0.24748 * 10 ** 3 / CCT + 0.23704)
y = -3 * x ** 2 + 2.87 * x - 0.275
xy = tstack((x, y))
return xy
def eotf_ARIBSTDB67(E_p, r=0.5):
"""
Defines *ARIB STD-B67 (Hybrid Log-Gamma)* electro-optical transfer
function (EOTF / EOCF).
Parameters
----------
E_p : numeric or array_like
Non-linear signal :math:`E'`.
r : numeric, optional
Video level corresponding to reference white level.
Returns
-------
numeric or ndarray
Voltage :math:`E` normalized by the reference white level and
proportional to the implicit light intensity that would be detected
with a reference camera color channel R, G, B.
Warning
-------
*ARIB STD-B67 (Hybrid Log-Gamma)* doesn't specify an electro-optical
transfer function. This definition is used for symmetry in unit tests and
other computations but should not be used as an *EOTF*.
Examples
--------
>>> eotf_ARIBSTDB67(0.212132034355964) # doctest: +ELLIPSIS
0.1799999...
"""
warning(('*ARIB STD-B67 (Hybrid Log-Gamma)* doesn\'t specify an '
'electro-optical transfer function. This definition is used '
'for symmetry in unit tests and others computations but should '
'not be used as an *EOTF*!'))
E_p = np.asarray(E_p)
a = ARIBSTDB67_CONSTANTS.a
b = ARIBSTDB67_CONSTANTS.b
c = ARIBSTDB67_CONSTANTS.c
E = np.where(E_p <= oetf_ARIBSTDB67(1), (E_p / r)**2,
np.exp((E_p - c) / a) + b)
return as_numeric(E)
def test_nan_first_order_colour_fit(self):
"""
Tests :func:`colour.characterisation.fitting.first_order_colour_fit`
definition nan support.
"""
cases = [-1.0, 0.0, 1.0, np.nan]
cases = set(permutations(cases * 3, r=3))
for case in cases:
try:
first_order_colour_fit(np.vstack((M1, case)),
np.vstack((M2, case)))
except ValueError:
import traceback
from colour.utilities import warning
warning(traceback.format_exc())
def test_nan_first_order_colour_fit(self):
"""
Tests :func:`colour.characterisation.fitting.first_order_colour_fit`
definition nan support.
"""
cases = [-1.0, 0.0, 1.0, np.nan]
cases = set(permutations(cases * 3, r=3))
for case in cases:
try:
first_order_colour_fit(np.vstack((M1, case)),
np.vstack((M2, case)))
except (ValueError, LinAlgError):
import traceback
from colour.utilities import warning
warning(traceback.format_exc())
def test_nan_normalised_primary_matrix(self):
"""
Tests :func:`colour.models.rgb.derivation.normalised_primary_matrix`
definition nan support.
"""
cases = [-1.0, 0.0, 1.0, -np.inf, np.inf, np.nan]
cases = set(permutations(cases * 3, r=2))
for case in cases:
P = np.array(np.vstack((case, case, case)))
W = np.array(case)
try:
normalised_primary_matrix(P, W)
except np.linalg.linalg.LinAlgError:
import traceback
from colour.utilities import warning
warning(traceback.format_exc())
def test_nan_normalised_primary_matrix(self):
"""
Tests :func:`colour.models.rgb.derivation.normalised_primary_matrix`
definition nan support.
"""
cases = [-1.0, 0.0, 1.0, -np.inf, np.inf, np.nan]
cases = set(permutations(cases * 3, r=2))
for case in cases:
P = np.array(np.vstack((case, case, case)))
W = np.array(case)
try:
normalised_primary_matrix(P, W)
except np.linalg.linalg.LinAlgError:
import traceback
from colour.utilities import warning
warning(traceback.format_exc())
def test_nan__call__(self):
"""
Tests :func:`colour.algebra.interpolation.SpragueInterpolator.__call__`
method nan support.
"""
cases = [-1.0, 0.0, 1.0, -np.inf, np.inf, np.nan]
cases = set(permutations(cases * 3, r=3))
for case in cases:
try:
sprague_interpolator = SpragueInterpolator(
np.array(case), np.array(case))
sprague_interpolator(case[0])
except AssertionError:
import traceback
from colour.utilities import warning
warning(traceback.format_exc())
def range(self, value):
"""
Setter for the **self.range** property.
"""
if value is not None:
if not np.all(np.isfinite(value)):
warning('"range" variable is not finite, '
'unpredictable results may occur!\n{0}'.format(value))
value = np.copy(value).astype(self.dtype)
if self._domain is not None:
assert value.size == self._domain.size, (
'"domain" and "range" variables must have same size!')
self._range = value
self._create_function()
def test_nan__call__(self):
"""
Tests :func:`colour.algebra.interpolation.SpragueInterpolator.__call__`
method nan support.
"""
cases = [-1.0, 0.0, 1.0, -np.inf, np.inf, np.nan]
cases = set(permutations(cases * 3, r=3))
for case in cases:
try:
sprague_interpolator = SpragueInterpolator(
np.array(case), np.array(case))
sprague_interpolator(case[0])
except AssertionError:
import traceback
from colour.utilities import warning
warning(traceback.format_exc())
def lightness_Wyszecki1963(Y, **kwargs):
"""
Returns the *Lightness* :math:`W` of given *luminance* :math:`Y` using
*Wyszecki (1963)* method.
Parameters
----------
Y : numeric or array_like
*luminance* :math:`Y`.
\**kwargs : dict, optional
Unused parameter provided for signature compatibility with other
*Lightness* computation objects.
Returns
-------
numeric or array_like
*Lightness* :math:`W`.
Notes
-----
- Input *luminance* :math:`Y` is in domain [0, 100].
- Output *Lightness* :math:`W` is in domain [0, 100].
References
----------
.. [3] Wyszecki, G. (1963). Proposal for a New Color-Difference Formula.
J. Opt. Soc. Am., 53(11), 1318–1319. doi:10.1364/JOSA.53.001318
Examples
--------
>>> lightness_Wyszecki1963(10.08) # doctest: +ELLIPSIS
37.0041149...
"""
Y = np.asarray(Y)
if np.any(Y < 1) or np.any(Y > 98):
warning(('"W*" Lightness computation is only applicable for '
'1% < "Y" < 98%, unpredictable results may occur!'))
W = 25 * (Y**(1 / 3)) - 17
return W
def lightness_Wyszecki1963(Y, **kwargs):
"""
Returns the *Lightness* :math:`W` of given *luminance* :math:`Y` using
*Wyszecki (1963)* method.
Parameters
----------
Y : numeric or array_like
*luminance* :math:`Y`.
\**kwargs : dict, optional
Unused parameter provided for signature compatibility with other
*Lightness* computation objects.
Returns
-------
numeric or array_like
*Lightness* :math:`W`.
Notes
-----
- Input *luminance* :math:`Y` is in domain [0, 100].
- Output *Lightness* :math:`W` is in domain [0, 100].
References
----------
.. [3] Wyszecki, G. (1963). Proposal for a New Color-Difference Formula.
J. Opt. Soc. Am., 53(11), 1318–1319. doi:10.1364/JOSA.53.001318
Examples
--------
>>> lightness_Wyszecki1963(10.08) # doctest: +ELLIPSIS
37.0041149...
"""
Y = np.asarray(Y)
if np.any(Y < 1) or np.any(Y > 98):
warning(('"W*" Lightness computation is only applicable for '
'1% < "Y" < 98%, unpredictable results may occur!'))
W = 25 * (Y ** (1 / 3)) - 17
return W
def test_nan_RGB_luminance(self):
"""
Tests :func:`colour.models.rgb.derivation.RGB_luminance`
definition nan support.
"""
cases = [-1.0, 0.0, 1.0, -np.inf, np.inf, np.nan]
cases = set(permutations(cases * 3, r=3))
for case in cases:
RGB = np.array(case)
P = np.array(np.vstack((case[0:2], case[0:2], case[0:2])))
W = np.array(case[0:2])
try:
RGB_luminance(RGB, P, W)
except np.linalg.linalg.LinAlgError:
import traceback
from colour.utilities import warning
warning(traceback.format_exc())
def lightness_wyszecki1964(Y, **kwargs):
"""
Returns the *Lightness* :math:`W^*` of given *luminance* :math:`Y` using
*Wyszecki (1964)* method.
Parameters
----------
Y : numeric
*luminance* :math:`Y`.
\*\*kwargs : \*\*, optional
Unused parameter provided for signature compatibility with other
*Lightness* computation objects.
Returns
-------
numeric
*Lightness* :math:`W^*`.
Notes
-----
- Input *luminance* :math:`Y` is in domain [0, 100].
- Output *Lightness* :math:`W^*` is in domain [0, 100].
References
----------
.. [2] http://en.wikipedia.org/wiki/Lightness
(Last accessed 13 April 2014)
Examples
--------
>>> lightness_wyszecki1964(10.08) # doctest: +ELLIPSIS
37.0041149...
"""
if not 1 < Y < 98:
warning(('"W*" Lightness computation is only applicable for '
'1% < "Y" < 98%, unpredictable results may occur!'))
W = 25 * (Y**(1 / 3)) - 17
return W
def lightness_wyszecki1964(Y, **kwargs):
"""
Returns the *Lightness* :math:`W^*` of given *luminance* :math:`Y` using
*Wyszecki (1964)* method.
Parameters
----------
Y : numeric
*luminance* :math:`Y`.
\*\*kwargs : \*\*, optional
Unused parameter provided for signature compatibility with other
*Lightness* computation objects.
Returns
-------
numeric
*Lightness* :math:`W^*`.
Notes
-----
- Input *luminance* :math:`Y` is in domain [0, 100].
- Output *Lightness* :math:`W^*` is in domain [0, 100].
References
----------
.. [2] http://en.wikipedia.org/wiki/Lightness
(Last accessed 13 April 2014)
Examples
--------
>>> lightness_wyszecki1964(10.08) # doctest: +ELLIPSIS
37.0041149...
"""
if not 1 < Y < 98:
warning(('"W*" Lightness computation is only applicable for '
'1% < "Y" < 98%, unpredictable results may occur!'))
W = 25 * (Y ** (1 / 3)) - 17
return W
def test_nan_chromatic_adaptation_Fairchild1990(self):
"""
Tests :func:`colour.adaptation.fairchild1990.\
chromatic_adaptation_Fairchild1990` definition nan support.
"""
cases = [-1.0, 0.0, 1.0, -np.inf, np.inf, np.nan]
cases = set(permutations(cases * 3, r=3))
for case in cases:
XYZ_1 = np.array(case)
XYZ_n = np.array(case)
XYZ_r = np.array(case)
Y_n = case[0]
try:
chromatic_adaptation_Fairchild1990(XYZ_1, XYZ_n, XYZ_r, Y_n)
except np.linalg.linalg.LinAlgError:
import traceback
from colour.utilities import warning
warning(traceback.format_exc())
def test_nan_chromatic_adaptation_Fairchild1990(self):
"""
Tests :func:`colour.adaptation.fairchild1990.\
chromatic_adaptation_Fairchild1990` definition nan support.
"""
cases = [-1.0, 0.0, 1.0, -np.inf, np.inf, np.nan]
cases = set(permutations(cases * 3, r=3))
for case in cases:
XYZ_1 = np.array(case)
XYZ_n = np.array(case)
XYZ_r = np.array(case)
Y_n = case[0]
try:
chromatic_adaptation_Fairchild1990(XYZ_1, XYZ_n, XYZ_r, Y_n)
except np.linalg.linalg.LinAlgError:
import traceback
from colour.utilities import warning
warning(traceback.format_exc())
def load(dataset):
"""
Loads given dataset: The dataset is pulled locally, i.e. synced if required
and then its data is loaded.
Parameters
----------
dataset : unicode or int
Dataset id, i.e. the *Zenodo* record number or title.
Returns
-------
object
Dataset data.
Examples
--------
>>> len(load('3245883').keys())
28
>>> len(load(
... 'Camera Spectral Sensitivity Database - '
... 'Jiang et al. (2013)').keys())
28
"""
global _HAS_TITLE_KEYS
if not _HAS_TITLE_KEYS:
for key in list(DATASET_LOADERS.keys())[:]:
dataset_loader = datasets().get(key)
if not dataset_loader:
continue
title = dataset_loader.title
if title in DATASET_LOADERS:
warning('"{0}" key is already defined in the dataset loaders!'.
format(title))
DATASET_LOADERS[title] = DATASET_LOADERS[key]
_HAS_TITLE_KEYS = True
return DATASET_LOADERS[six.text_type(dataset)]().content
def lightness_Wyszecki1963(Y):
"""
Returns the *Lightness* :math:`W` of given *luminance* :math:`Y` using
*Wyszecki (1963)* method.
Parameters
----------
Y : numeric or array_like
*luminance* :math:`Y`.
Returns
-------
numeric or array_like
*Lightness* :math:`W`.
Notes
-----
- Input *luminance* :math:`Y` is in domain [0, 100].
- Output *Lightness* :math:`W` is in range [0, 100].
References
----------
- :cite:`Wyszecki1963b`
Examples
--------
>>> lightness_Wyszecki1963(10.08) # doctest: +ELLIPSIS
37.0041149...
"""
Y = np.asarray(Y)
if np.any(Y < 1) or np.any(Y > 98):
warning(('"W*" Lightness computation is only applicable for '
'1% < "Y" < 98%, unpredictable results may occur!'))
W = 25 * (Y**(1 / 3)) - 17
return W
def domain(self, value):
"""
Setter for the **self.domain** property.
"""
if value is not None:
if not np.all(np.isfinite(value)):
warning('"domain" variable is not finite, '
'unpredictable results may occur!\n{0}'.format(value))
value = np.copy(value).astype(self.dtype)
if self._range is not None:
if value.size != self._range.size:
warning(
'"domain" and "range" variables have different size, '
'"range" variable will be resized to '
'"domain" variable shape!')
self._range = np.resize(self._range, value.shape)
self._domain = value
self._create_function()
def eotf_BT709(V):
"""
Defines *Recommendation ITU-R BT.709-6* electro-optical transfer function
(EOTF / EOCF).
Parameters
----------
V : numeric or array_like
Electrical signal :math:`V`.
Returns
-------
numeric or ndarray
Corresponding *luminance* :math:`L` of the image.
Warning
-------
*Recommendation ITU-R BT.709-6* doesn't specify an electro-optical
transfer function. This definition is used for symmetry in unit tests and
other computations but should not be used as an *EOTF*.
Examples
--------
>>> eotf_BT709(0.409007728864150) # doctest: +ELLIPSIS
0.1...
"""
warning(('*Recommendation ITU-R BT.709-6* doesn\'t specify an '
'electro-optical transfer function. This definition is used '
'for symmetry in unit tests and others computations but should '
'not be used as an *EOTF*!'))
V = np.asarray(V)
return as_numeric(
np.where(V < oetf_BT709(0.018), V / 4.5,
((V + 0.099) / 1.099)**(1 / 0.45)))
def eotf_BT709(V):
"""
Defines *Recommendation ITU-R BT.709-6* electro-optical transfer function
(EOTF / EOCF).
Parameters
----------
V : numeric or array_like
Electrical signal :math:`V`.
Returns
-------
numeric or ndarray
Corresponding *luminance* :math:`L` of the image.
Warning
-------
*Recommendation ITU-R BT.709-6* doesn't specify an electro-optical
transfer function. This definition is used for symmetry in unit tests and
other computations but should not be used as an *EOTF*.
Examples
--------
>>> eotf_BT709(0.409007728864150) # doctest: +ELLIPSIS
0.1...
"""
warning(('*Recommendation ITU-R BT.709-6* doesn\'t specify an '
'electro-optical transfer function. This definition is used '
'for symmetry in unit tests and others computations but should '
'not be used as an *EOTF*!'))
V = np.asarray(V)
return as_numeric(np.where(V < oetf_BT709(0.018),
V / 4.5,
((V + 0.099) / 1.099) ** (1 / 0.45)))
def CCT_to_xy_Kang2002(CCT):
"""
Returns the *CIE XYZ* tristimulus values *xy* chromaticity coordinates from
given correlated colour temperature :math:`T_{cp}` using Kang et al. (2002)
method.
Parameters
----------
CCT : numeric or array_like
Correlated colour temperature :math:`T_{cp}`.
Returns
-------
ndarray
*xy* chromaticity coordinates.
Raises
------
ValueError
If the correlated colour temperature is not in appropriate domain.
References
----------
.. [11] Kang, B., Moon, O., Hong, C., Lee, H., Cho, B., & Kim, Y. (2002).
Design of advanced color: Temperature control system for HDTV
applications. Journal of the Korean …, 41(6), 865–871. Retrieved
from http://cat.inist.fr/?aModele=afficheN&cpsidt=14448733
Examples
--------
>>> CCT_to_xy_Kang2002(6504.38938305) # doctest: +ELLIPSIS
array([ 0.313426..., 0.3235959...])
"""
CCT = np.asarray(CCT)
if np.any(CCT[np.asarray(np.logical_or(CCT < 1667, CCT > 25000))]):
warning(('Correlated colour temperature must be in domain '
'[1667, 25000], unpredictable results may occur!'))
x = np.where(CCT <= 4000,
-0.2661239 * 10 ** 9 / CCT ** 3 -
0.2343589 * 10 ** 6 / CCT ** 2 +
0.8776956 * 10 ** 3 / CCT +
0.179910,
-3.0258469 * 10 ** 9 / CCT ** 3 +
2.1070379 * 10 ** 6 / CCT ** 2 +
0.2226347 * 10 ** 3 / CCT +
0.24039)
y = np.select([CCT <= 2222,
np.logical_and(CCT > 2222, CCT <= 4000),
CCT > 4000],
[-1.1063814 * x ** 3 -
1.34811020 * x ** 2 +
2.18555832 * x -
0.20219683,
-0.9549476 * x ** 3 -
1.37418593 * x ** 2 +
2.09137015 * x -
0.16748867,
3.0817580 * x ** 3 -
5.8733867 * x ** 2 +
3.75112997 * x -
0.37001483])
xy = tstack((x, y))
return xy
"""
Interpolates a 1-D function using cubic spline interpolation.
Notes
-----
This class is a wrapper around *scipy.interpolate.interp1d* class.
"""
def __init__(self, *args, **kwargs):
# TODO: Implements proper wrapper to ensure return values
# consistency and avoid having to cast to numeric in
# :meth:`SpectralPowerDistribution.interpolate` method.
super(SplineInterpolator, self).__init__(
kind='cubic', *args, **kwargs)
else:
warning(('"scipy.interpolate.interp1d" interpolator is unavailable, using '
'"LinearInterpolator1d" instead!'))
SplineInterpolator = LinearInterpolator1d
class SpragueInterpolator(object):
"""
Constructs a fifth-order polynomial that passes through :math:`y` dependent
variable.
Sprague (1880) method is recommended by the *CIE* for interpolating
functions having a uniformly spaced independent variable.
Parameters
----------
x : array_like
def main():
"""
Starts the application.
Return
------
bool
Definition success.
"""
arguments = command_line_arguments()
if arguments.version:
print('{0} - {1}'.format(__application_name__, __version__))
return True
settings = json.load(open(SETTINGS_FILE))
if arguments.settings_file is not None:
assert os.path.exists(
arguments.settings_file), ('"{0}" file doesn\'t exists!'.format(
arguments.settings_file))
settings.update(json.load(open(arguments.settings_file)))
input_linearity = arguments.input_linearity.lower()
if input_linearity == 'linear':
input_linear = True
elif input_linearity == 'oecf':
input_linear = False
else:
input_extension = os.path.splitext(arguments.input_image)[1].lower()
if input_extension in LINEAR_IMAGE_FORMATS:
input_linear = True
else:
input_linear = False
if arguments.input_image is not None:
assert os.path.exists(arguments.input_image), (
'"{0}" input image doesn\'t exists!'.format(arguments.input_image))
image_path = arguments.input_image
else:
image_path = DEFAULT_IMAGE_PATH
try:
image = read_image(str(image_path))
if not input_linear:
colourspace = RGB_COLOURSPACES[arguments.input_oecf]
image = colourspace.decoding_cctf(image)
# Keeping RGB channels only.
image = image[..., 0:3]
image = image[::int(arguments.input_resample), ::int(
arguments.input_resample)]
except ImportError:
warning(
'"OpenImageIO" is not available, image reading is not supported, '
'falling back to some random noise!')
image = None
if not arguments.enable_warnings:
warnings.filterwarnings("ignore")
ColourAnalysis(image, arguments.input_image, arguments.input_colourspace,
arguments.input_oecf, input_linear,
arguments.reference_colourspace,
arguments.correlate_colourspace, settings, arguments.layout)
return run()
def uv_to_CCT_Ohno2013(uv,
cmfs=STANDARD_OBSERVERS_CMFS.get(
'CIE 1931 2 Degree Standard Observer'),
start=CCT_MINIMAL,
end=CCT_MAXIMAL,
count=CCT_SAMPLES,
iterations=CCT_CALCULATION_ITERATIONS):
"""
Returns the correlated colour temperature :math:`T_{cp}` and
:math:`\Delta_{uv}` from given *CIE UCS* colourspace *uv* chromaticity
coordinates, colour matching functions and temperature range using
Ohno (2013) method.
The iterations parameter defines the calculations precision: The higher its
value, the more planckian tables will be generated through cascade
expansion in order to converge to the exact solution.
Parameters
----------
uv : array_like
*CIE UCS* colourspace *uv* chromaticity coordinates.
cmfs : XYZ_ColourMatchingFunctions, optional
Standard observer colour matching functions.
start : numeric, optional
Temperature range start in kelvins.
end : numeric, optional
Temperature range end in kelvins.
count : int, optional
Temperatures count in the planckian tables.
iterations : int, optional
Number of planckian tables to generate.
Returns
-------
ndarray
Correlated colour temperature :math:`T_{cp}`, :math:`\Delta_{uv}`.
References
----------
.. [3] Ohno, Y. (2014). Practical Use and Calculation of CCT and Duv.
LEUKOS, 10(1), 47–55. doi:10.1080/15502724.2014.839020
Examples
--------
>>> from colour import STANDARD_OBSERVERS_CMFS
>>> cmfs = 'CIE 1931 2 Degree Standard Observer'
>>> cmfs = STANDARD_OBSERVERS_CMFS.get(cmfs)
>>> uv = np.array([0.1978, 0.3122])
>>> uv_to_CCT_Ohno2013(uv, cmfs) # doctest: +ELLIPSIS
array([ 6.5075470...e+03, 3.2236908...e-03])
"""
# Ensuring we do at least one iteration to initialise variables.
if iterations <= 0:
iterations = 1
# Planckian table creation through cascade expansion.
for _i in range(iterations):
table = planckian_table(uv, cmfs, start, end, count)
index = planckian_table_minimal_distance_index(table)
if index == 0:
warning(
('Minimal distance index is on lowest planckian table bound, '
'unpredictable results may occur!'))
index += 1
elif index == len(table) - 1:
warning(
('Minimal distance index is on highest planckian table bound, '
'unpredictable results may occur!'))
index -= 1
start = table[index - 1].Ti
end = table[index + 1].Ti
_ux, vx = uv
Tuvdip, Tuvdi, Tuvdin = (table[index - 1], table[index], table[index + 1])
Tip, uip, vip, dip = Tuvdip.Ti, Tuvdip.ui, Tuvdip.vi, Tuvdip.di
Ti, di = Tuvdi.Ti, Tuvdi.di
Tin, uin, vin, din = Tuvdin.Ti, Tuvdin.ui, Tuvdin.vi, Tuvdin.di
# Triangular solution.
l = np.sqrt((uin - uip) ** 2 + (vin - vip) ** 2)
x = (dip ** 2 - din ** 2 + l ** 2) / (2 * l)
T = Tip + (Tin - Tip) * (x / l)
vtx = vip + (vin - vip) * (x / l)
sign = 1 if vx - vtx >= 0 else -1
D_uv = (dip ** 2 - x ** 2) ** (1 / 2) * sign
# Parabolic solution.
if D_uv < 0.002:
X = (Tin - Ti) * (Tip - Tin) * (Ti - Tip)
a = (Tip * (din - di) + Ti * (dip - din) + Tin * (di - dip)) * X ** -1
b = (-(Tip ** 2 * (din - di) + Ti ** 2 * (dip - din) + Tin ** 2 *
(di - dip)) * X ** -1)
c = (-(dip * (Tin - Ti) * Ti * Tin + di * (Tip - Tin) * Tip * Tin
+ din * (Ti - Tip) * Tip * Ti) * X ** -1)
T = -b / (2 * a)
D_uv = sign * (a * T ** 2 + b * T + c)
return np.array([T, D_uv])
def XYZ_to_Hunt(XYZ,
XYZ_w,
XYZ_b,
L_A,
surround=HUNT_VIEWING_CONDITIONS.get('Normal Scenes'),
L_AS=None,
CCT_w=None,
XYZ_p=None,
p=None,
S=None,
S_W=None,
helson_judd_effect=False,
discount_illuminant=True):
"""
Computes the *Hunt* colour appearance model correlates.
Parameters
----------
XYZ : array_like, (3,)
*CIE XYZ* colourspace matrix of test sample / stimulus in domain
[0, 100].
XYZ_w : array_like, (3,)
*CIE XYZ* colourspace matrix of reference white in domain [0, 100].
XYZ_b : array_like, (3,)
*CIE XYZ* colourspace matrix of background in domain [0, 100].
L_A : numeric
Adapting field *luminance* :math:`L_A` in :math:`cd/m^2`.
surround : Hunt_InductionFactors, optional
Surround viewing conditions induction factors.
L_AS : numeric, optional
Scotopic luminance :math:`L_{AS}` of the illuminant, approximated if
not specified.
CCT_w : numeric, optional
Correlated color temperature :math:`T_{cp}`: of the illuminant, needed
to approximate :math:`L_{AS}`.
XYZ_p : array_like, (3,), optional
*CIE XYZ* colourspace matrix of proximal field in domain [0, 100],
assumed to be equal to background if not specified.
p : numeric, optional
Simultaneous contrast / assimilation factor :math:`p` with value in
domain [-1, 0] when simultaneous contrast occurs and domain [0, 1]
when assimilation occurs.
S : numeric, optional
Scotopic response :math:`S` to the stimulus, approximated using
tristimulus values :math:`Y` of the stimulus if not specified.
S_w : numeric, optional
Scotopic response :math:`S_w` for the reference white, approximated
using the tristimulus values :math:`Y_w` of the reference white if not
specified.
helson_judd_effect : bool, optional
Truth value indicating whether the *Helson-Judd* effect should be
accounted for.
discount_illuminant : bool, optional
Truth value indicating if the illuminant should be discounted.
Warning
-------
The input domain of that definition is non standard!
Notes
-----
- Input *CIE XYZ* colourspace matrix is in domain [0, 100].
- Input *CIE XYZ_b* colourspace matrix is in domain [0, 100].
- Input *CIE XYZ_w* colourspace matrix is in domain [0, 100].
- Input *CIE XYZ_p* colourspace matrix is in domain [0, 100].
Returns
-------
Hunt_Specification
*Hunt* colour appearance model specification.
Raises
------
ValueError
If an illegal arguments combination is specified.
Examples
--------
>>> XYZ = np.array([19.01, 20.00, 21.78])
>>> XYZ_w = np.array([95.05, 100.00, 108.88])
>>> XYZ_b = np.array([95.05, 100.00, 108.88])
>>> L_A = 318.31
>>> surround = HUNT_VIEWING_CONDITIONS['Normal Scenes']
>>> CCT_w = 6504.0
>>> XYZ_to_Hunt(XYZ, XYZ_w, XYZ_b, L_A, surround, CCT_w=CCT_w) # noqa # doctest: +ELLIPSIS
Hunt_Specification(J=30.0462678..., C=0.1210508..., h=269.2737594..., s=0.0199093..., Q=22.2097654..., M=0.1238964..., H=None, HC=None)
"""
X, Y, Z = np.ravel(XYZ)
X_b, Y_b, Z_b = np.ravel(XYZ_b)
X_w, Y_w, Z_w = np.ravel(XYZ_w)
# Arguments handling.
if XYZ_p is not None:
X_p, Y_p, Z_p = np.ravel(XYZ_p)
else:
X_p = X_b
Y_p = Y_b
Z_p = Y_b
warning('Unspecified proximal field "XYZ_p" argument, using '
'background "XYZ_b" as approximation!')
if surround.N_cb is None:
N_cb = 0.725 * (Y_w / Y_b) ** 0.2
warning('Unspecified "N_cb" argument, using approximation: '
'"{0}"'.format(N_cb))
if surround.N_bb is None:
N_bb = 0.725 * (Y_w / Y_b) ** 0.2
warning('Unspecified "N_bb" argument, using approximation: '
'"{0}"'.format(N_bb))
if L_AS is None and CCT_w is None:
raise ValueError('Either the scotopic luminance "L_AS" of the '
'illuminant or its correlated colour temperature '
'"CCT_w" must be specified!')
if L_AS is None:
L_AS = illuminant_scotopic_luminance(L_A, CCT_w)
warning('Unspecified "L_AS" argument, using approximation from "CCT": '
'"{0}"'.format(L_AS))
if S is None != S_W is None:
raise ValueError('Either both stimulus scotopic response "S" and '
'reference white scotopic response "S_w" arguments '
'need to be specified or none of them!')
elif S is None and S_W is None:
S = Y
S_W = Y_w
warning('Unspecified stimulus scotopic response "S" and reference '
'white scotopic response "S_w" arguments, using '
'approximation: "{0}", "{1}"'.format(S, S_W))
if p is None:
warning('Unspecified simultaneous contrast / assimilation "p" '
'argument, model will not account for simultaneous chromatic '
'contrast!')
XYZ_p = np.array([X_p, Y_p, Z_p])
# Computing luminance level adaptation factor :math:`F_L`.
F_L = luminance_level_adaptation_factor(L_A)
# Computing test sample chromatic adaptation.
rgb_a = chromatic_adaptation(XYZ,
XYZ_w,
XYZ_b,
L_A,
F_L,
XYZ_p,
p,
helson_judd_effect,
discount_illuminant)
# Computing reference white chromatic adaptation.
rgb_aw = chromatic_adaptation(XYZ_w,
XYZ_w,
XYZ_b,
L_A,
F_L,
XYZ_p,
p,
helson_judd_effect,
discount_illuminant)
# Computing opponent colour dimensions.
# Computing achromatic post adaptation signals.
A_a = achromatic_post_adaptation_signal(rgb_a)
A_aw = achromatic_post_adaptation_signal(rgb_aw)
# Computing colour difference signals.
C = colour_difference_signals(rgb_a)
C_w = colour_difference_signals(rgb_aw)
# -------------------------------------------------------------------------
# Computing the *hue* angle :math:`h_s`.
# -------------------------------------------------------------------------
h = hue_angle(C)
hue_w = hue_angle(C_w)
# TODO: Implement hue quadrature & composition computation.
# -------------------------------------------------------------------------
# Computing the correlate of *saturation* :math:`s`.
# -------------------------------------------------------------------------
# Computing eccentricity factors.
e_s = eccentricity_factor(h)
e_s_w = eccentricity_factor(hue_w)
# Computing low luminance tritanopia factor :math:`F_t`.
F_t = low_luminance_tritanopia_factor(L_A)
M_yb = yellowness_blueness_response(C, e_s, surround.N_c, N_cb, F_t)
M_rg = redness_greenness_response(C, e_s, surround.N_c, N_cb)
M_yb_w = yellowness_blueness_response(C_w, e_s, surround.N_c, N_cb, F_t)
M_rg_w = redness_greenness_response(C_w, e_s, surround.N_c, N_cb)
# Computing overall chromatic response.
M = overall_chromatic_response(M_yb, M_rg)
M_w = overall_chromatic_response(M_yb_w, M_rg_w)
s = saturation_correlate(M, rgb_a)
# -------------------------------------------------------------------------
# Computing the correlate of *brightness* :math:`Q`.
# -------------------------------------------------------------------------
# Computing achromatic signal :math:`A`.
A = achromatic_signal(L_AS, S, S_W, N_bb, A_a)
A_w = achromatic_signal(L_AS, S_W, S_W, N_bb, A_aw)
Q = brightness_correlate(A, A_w, M, surround.N_b)
brightness_w = brightness_correlate(A_w, A_w, M_w, surround.N_b)
# TODO: Implement whiteness-blackness :math:`Q_{wb}` computation.
# -------------------------------------------------------------------------
# Computing the correlate of *Lightness* :math:`J`.
# -------------------------------------------------------------------------
J = lightness_correlate(Y_b, Y_w, Q, brightness_w)
# -------------------------------------------------------------------------
# Computing the correlate of *chroma* :math:`C_{94}`.
# -------------------------------------------------------------------------
C_94 = chroma_correlate(s,
Y_b,
Y_w,
Q,
brightness_w)
# -------------------------------------------------------------------------
# Computing the correlate of *colourfulness* :math:`M_{94}`.
# -------------------------------------------------------------------------
M_94 = colourfulness_correlate(F_L, C_94)
return Hunt_Specification(J, C_94, h, s, Q, M_94, None, None)
"""
Property for **self.__y** private attribute.
Returns
-------
array_like
self.__y
"""
return self.__y
@y.setter
def y(self, value):
"""
Setter for **self.__y** private attribute.
Parameters
----------
value : array_like
Attribute value.
"""
raise AttributeError('"{0}" attribute is read only!'.format('y'))
else:
warning(('"scipy.interpolate.PchipInterpolator" and '
'"scipy.interpolate.interp1d" interpolators are not available, '
'using "LinearInterpolator" instead!'))
PchipInterpolator = CubicSplineInterpolator = LinearInterpolator
def colour_quality_bars_plot(specifications,
labels=True,
hatching=None,
hatching_repeat=1,
**kwargs):
"""
Plots the colour quality data of given illuminants or light sources colour
quality specifications.
Parameters
----------
specifications : array_like
Array of illuminants or light sources colour quality specifications.
labels : bool, optional
Add labels above bars.
hatching : bool or None, optional
Use hatching for the bars.
hatching_repeat : int, optional
Hatching pattern repeat.
\**kwargs : dict, optional
Keywords arguments.
Returns
-------
bool
Definition success.
Examples
--------
>>> from colour import (
... ILLUMINANTS_RELATIVE_SPDS,
... LIGHT_SOURCES_RELATIVE_SPDS)
>>> illuminant = ILLUMINANTS_RELATIVE_SPDS.get('F2')
>>> light_source = LIGHT_SOURCES_RELATIVE_SPDS.get('Kinoton 75P')
>>> cqs_i = colour_quality_scale(illuminant, additional_data=True)
>>> cqs_l = colour_quality_scale(light_source, additional_data=True)
>>> colour_quality_bars_plot([cqs_i, cqs_l]) # doctest: +SKIP
True
"""
settings = {'figure_size': (DEFAULT_FIGURE_WIDTH, DEFAULT_FIGURE_WIDTH)}
settings.update(kwargs)
canvas(**settings)
bar_width = 0.5
y_ticks_steps = 10
count_s, count_Q_as = len(specifications), 0
patterns = cycle(DEFAULT_HATCH_PATTERNS)
if hatching is None:
hatching = False if count_s == 1 else True
for i, specification in enumerate(specifications):
Q_a, Q_as, colorimetry_data = (specification.Q_a,
specification.Q_as,
specification.colorimetry_data)
count_Q_as = len(Q_as)
colours = ([[1] * 3] + [np.clip(XYZ_to_sRGB(x.XYZ), 0, 1)
for x in colorimetry_data[0]])
x = (i + np.arange(0, (count_Q_as + 1) * (count_s + 1), (count_s + 1),
dtype=np.float)) * bar_width
y = [s[1].Q_a for s in sorted(Q_as.items(), key=lambda s: s[0])]
y = np.array([Q_a] + list(y))
if np.sign(np.min(y)) < 0:
warning(
('"{0}" spectral distribution has negative "Q_a" value(s), '
'using absolute value(s) '
'for plotting purpose!'.format(specification.name)))
y = np.abs(y)
bars = pylab.bar(x,
y,
color=colours,
width=bar_width,
hatch=(next(patterns) * hatching_repeat
if hatching else None),
label=specification.name)
if labels:
label_rectangles(
bars,
rotation='horizontal' if count_s == 1 else 'vertical',
offset=(0 if count_s == 1 else 3 / 100 * count_s + 65 / 1000,
0.025),
text_size=-5 / 7 * count_s + 12.5)
pylab.axhline(y=100, color='black', linestyle='--')
pylab.xticks((np.arange(0, (count_Q_as + 1) * (count_s + 1), (count_s + 1),
dtype=np.float) *
bar_width + (count_s * bar_width / 2)),
['Qa'] + ['Q{0}'.format(index + 1)
for index in range(0, count_Q_as + 1, 1)])
pylab.yticks(range(0, 100 + y_ticks_steps, y_ticks_steps))
settings.update({
'title': 'Colour Quality',
'legend': hatching,
'x_tighten': True,
'y_tighten': True,
'limits': (-bar_width,
((count_Q_as + 1) * (count_s + 1)) / 2,
0,
120),
'aspect': 1 / (120 / (bar_width + len(Q_as) + bar_width * 2))})
settings.update(kwargs)
boundaries(**settings)
decorate(**settings)
return display(**settings)
class TestRGBLuminance(unittest.TestCase):
"""
Defines :func:`colour.models.rgb.derivation.RGB_luminance` definition
unit tests methods.
"""
def test_RGB_luminance(self):
"""
Tests:func:`colour.models.rgb.derivation.RGB_luminance`
definition.
"""
self.assertAlmostEqual(RGB_luminance(
np.array([50.0, 50.0, 50.0]),
np.array([0.73470, 0.26530, 0.00000, 1.00000, 0.00010, -0.07700]),
np.array([0.32168, 0.33767])),
50.00000000,
places=7)
self.assertAlmostEqual(RGB_luminance(
np.array([74.6, 16.1, 100.0]),
np.array([0.73470, 0.26530, 0.00000, 1.00000, 0.00010, -0.07700]),
np.array([0.32168, 0.33767])),
30.17011667,
places=7)
self.assertAlmostEqual(RGB_luminance(
np.array([40.6, 4.2, 67.4]),
np.array([0.73470, 0.26530, 0.00000, 1.00000, 0.00010, -0.07700]),
np.array([0.32168, 0.33767])),
12.16160184,
places=7)
def test_n_dimensional_RGB_luminance(self):
"""
Tests:func:`colour.models.rgb.derivation.RGB_luminance` definition
n_dimensional arrays support.
"""
RGB = np.array([50.0, 50.0, 50.0]),
P = np.array([0.73470, 0.26530, 0.00000, 1.00000, 0.00010, -0.07700]),
W = np.array([0.32168, 0.33767])
Y = 50
np.testing.assert_almost_equal(RGB_luminance(RGB, P, W), Y)
RGB = np.tile(RGB, (6, 1))
Y = np.tile(Y, 6)
np.testing.assert_almost_equal(RGB_luminance(RGB, P, W), Y)
RGB = np.reshape(RGB, (2, 3, 3))
Y = np.reshape(Y, (2, 3))
np.testing.assert_almost_equal(RGB_luminance(RGB, P, W), Y)
@ignore_numpy_errors
def test_nan_RGB_luminance(self):
"""
Tests :func:`colour.models.rgb.derivation.RGB_luminance`
definition nan support.
"""
cases = [-1.0, 0.0, 1.0, -np.inf, np.inf, np.nan]
cases = set(permutations(cases * 3, r=3))
for case in cases:
RGB = np.array(case)
P = np.array(np.vstack((case[0:2], case[0:2], case[0:2])))
W = np.array(case[0:2])
try:
RGB_luminance(RGB, P, W)
except np.linalg.linalg.LinAlgError:
import traceback
from colour.utilities import warning
warning(traceback.format_exc())
RAW_D_CONVERSION_ARGUMENTS.__doc__ = """
Arguments for the command line raw conversion application for demosaiced
linear *tiff* file format output.
RAW_D_CONVERSION_ARGUMENTS : unicode
"""
if _IS_MACOS_PLATFORM:
DNG_CONVERTER = DocstringText(
'/Applications/Adobe DNG Converter.app/Contents/'
'MacOS/Adobe DNG Converter')
elif _IS_WINDOWS_PLATFORM:
DNG_CONVERTER = DocstringText('Adobe DNG Converter')
else:
DNG_CONVERTER = None
warning('"Adobe DNG Converter" is not available on your platform!')
if DNG_CONVERTER is not None:
DNG_CONVERTER.__doc__ = """
Command line *DNG* conversion application, usually *Adobe DNG Converter*.
DNG_CONVERTER : unicode
"""
DNG_CONVERSION_ARGUMENTS = DocstringText('-cr7.1 -l -d "{0}" "{1}"')
if _IS_WINDOWS_PLATFORM:
DNG_CONVERSION_ARGUMENTS = DocstringText(
DNG_CONVERSION_ARGUMENTS.replace('"', ''))
DNG_CONVERSION_ARGUMENTS.__doc__ = """
Arguments for the command line *dng* conversion application.
def colour_quality_bars_plot(specifications,
labels=True,
hatching=None,
hatching_repeat=1,
**kwargs):
"""
Plots the colour quality data of given illuminants or light sources colour
quality specifications.
Parameters
----------
specifications : array_like
Array of illuminants or light sources colour quality specifications.
labels : bool, optional
Add labels above bars.
hatching : bool or None, optional
Use hatching for the bars.
hatching_repeat : int, optional
Hatching pattern repeat.
Other Parameters
----------------
\**kwargs : dict, optional
{:func:`boundaries`, :func:`canvas`, :func:`decorate`,
:func:`display`},
Please refer to the documentation of the previously listed definitions.
Returns
-------
Figure
Current figure or None.
Examples
--------
>>> from colour import (
... ILLUMINANTS_RELATIVE_SPDS,
... LIGHT_SOURCES_RELATIVE_SPDS,
... SpectralShape)
>>> illuminant = ILLUMINANTS_RELATIVE_SPDS['F2']
>>> light_source = LIGHT_SOURCES_RELATIVE_SPDS['Kinoton 75P']
>>> light_source = light_source.clone().align(SpectralShape(360, 830, 1))
>>> cqs_i = colour_quality_scale(illuminant, additional_data=True)
>>> cqs_l = colour_quality_scale(light_source, additional_data=True)
>>> colour_quality_bars_plot([cqs_i, cqs_l]) # doctest: +SKIP
"""
settings = {'figure_size': (DEFAULT_FIGURE_WIDTH, DEFAULT_FIGURE_WIDTH)}
settings.update(kwargs)
canvas(**settings)
bar_width = 0.5
y_ticks_interval = 10
count_s, count_Q_as = len(specifications), 0
patterns = cycle(DEFAULT_HATCH_PATTERNS)
if hatching is None:
hatching = False if count_s == 1 else True
for i, specification in enumerate(specifications):
Q_a, Q_as, colorimetry_data = (specification.Q_a, specification.Q_as,
specification.colorimetry_data)
count_Q_as = len(Q_as)
colours = (
[[1] * 3] +
[np.clip(XYZ_to_sRGB(x.XYZ), 0, 1) for x in colorimetry_data[0]])
x = (i + np.arange(0, (count_Q_as + 1) * (count_s + 1), (count_s + 1),
dtype=np.float_)) * bar_width
y = [s[1].Q_a for s in sorted(Q_as.items(), key=lambda s: s[0])]
y = np.array([Q_a] + list(y))
if np.sign(np.min(y)) < 0:
warning(
('"{0}" spectral distribution has negative "Q_a" value(s), '
'using absolute value(s) '
'for plotting purpose!'.format(specification.name)))
y = np.abs(y)
bars = pylab.bar(x,
y,
color=colours,
width=bar_width,
hatch=(next(patterns) *
hatching_repeat if hatching else None),
label=specification.name)
if labels:
label_rectangles(
bars,
rotation='horizontal' if count_s == 1 else 'vertical',
offset=(0 if count_s == 1 else 3 / 100 * count_s + 65 / 1000,
0.025),
text_size=-5 / 7 * count_s + 12.5)
pylab.axhline(y=100, color='black', linestyle='--')
pylab.xticks(
(np.arange(0, (count_Q_as + 1) * (count_s + 1), (count_s + 1),
dtype=np.float_) * bar_width + (count_s * bar_width / 2)),
['Qa'] +
['Q{0}'.format(index + 1) for index in range(0, count_Q_as + 1, 1)])
pylab.yticks(range(0, 100 + y_ticks_interval, y_ticks_interval))
settings.update({
'title':
'Colour Quality',
'legend':
hatching,
'x_tighten':
True,
'y_tighten':
True,
'limits': (-bar_width, ((count_Q_as + 1) * (count_s + 1)) / 2, 0, 120),
'aspect':
1 / (120 / (bar_width + len(Q_as) + bar_width * 2))
})
settings.update(kwargs)
boundaries(**settings)
decorate(**settings)
return display(**settings)
def XYZ_to_Nayatani95(XYZ,
XYZ_n,
Y_o,
E_o,
E_or,
n=1):
"""
Computes the Nayatani (1995) colour appearance model correlates.
Parameters
----------
XYZ : array_like, (3,)
*CIE XYZ* colourspace matrix of test sample / stimulus in domain
[0, 100].
XYZ_n : array_like, (3,)
*CIE XYZ* colourspace matrix of reference white in domain [0, 100].
Y_o : numeric
Luminance factor :math:`Y_o` of achromatic background as percentage in
domain [0.18, 1.0]
E_o : numeric
Illuminance :math:`E_o` of the viewing field in lux.
E_or : numeric
Normalising illuminance :math:`E_{or}` in lux usually in domain
[1000, 3000]
n : numeric, optional
Noise term used in the non linear chromatic adaptation model.
Returns
-------
Nayatani95_Specification
Nayatani (1995) colour appearance model specification.
Warning
-------
The input domain of that definition is non standard!
Notes
-----
- Input *CIE XYZ* colourspace matrix is in domain [0, 100].
- Input *CIE XYZ_n* colourspace matrix is in domain [0, 100].
Examples
--------
>>> XYZ = np.array([19.01, 20, 21.78])
>>> XYZ_n = np.array([95.05, 100, 108.88])
>>> Y_o = 20.0
>>> E_o = 5000.0
>>> E_or = 1000.0
>>> XYZ_to_Nayatani95(XYZ, XYZ_n, Y_o, E_o, E_or) # doctest: +ELLIPSIS
Nayatani95_Specification(Lstar_P=49.9998829..., C=0.0133550..., h=257.5232268..., s=0.0133550..., Q=62.6266734..., M=0.0167262..., H=None, HC=None, Lstar_N=50.0039154...)
"""
if not 18 <= Y_o <= 100:
warning(('"Y_o" luminance factor must be in [18, 100] domain, '
'unpredictable results may occur!'))
X, Y, Z = np.ravel(XYZ)
# Computing adapting luminance :math:`L_o` and normalising luminance
# :math:`L_{or}` in in :math:`cd/m^2`.
# L_o = illuminance_to_luminance(E_o, Y_o)
L_or = illuminance_to_luminance(E_or, Y_o)
# Computing :math:`\xi`, :math:`\eta`, :math:`\zeta` values.
xi, eta, zeta = xez = intermediate_values(XYZ_to_xy(XYZ_n))
# Computing adapting field cone responses.
RGB_o = ((Y_o * E_o) / (100 * np.pi)) * xez
# Computing stimulus cone responses.
R, G, B = RGB = XYZ_to_RGB_Nayatani95(np.array([X, Y, Z]))
# Computing exponential factors of the chromatic adaptation.
bRGB_o = exponential_factors(RGB_o)
bL_or = beta_1(L_or)
# Computing scaling coefficients :math:`e(R)` and :math:`e(G)`
eR = scaling_coefficient(R, xi)
eG = scaling_coefficient(G, eta)
# Computing opponent colour dimensions.
# Computing achromatic response :math:`Q`:
Q_response = achromatic_response(RGB, bRGB_o, xez,
bL_or, eR, eG, n)
# Computing tritanopic response :math:`t`:
t_response = tritanopic_response(RGB, bRGB_o, xez, n)
# Computing protanopic response :math:`p`:
p_response = protanopic_response(RGB, bRGB_o, xez, n)
# -------------------------------------------------------------------------
# Computing the correlate of *brightness* :math:`B_r`.
# -------------------------------------------------------------------------
B_r = brightness_correlate(bRGB_o, bL_or, Q_response)
# Computing *brightness* :math:`B_{rw}` of ideal white.
brightness_ideal_white = ideal_white_brightness_correlate(bRGB_o,
xez,
bL_or,
n)
# -------------------------------------------------------------------------
# Computing the correlate of achromatic *Lightness* :math:`L_p^\star`.
# -------------------------------------------------------------------------
Lstar_P = (
achromatic_lightness_correlate(Q_response))
# -------------------------------------------------------------------------
# Computing the correlate of normalised achromatic *Lightness*
# :math:`L_n^\star`.
# -------------------------------------------------------------------------
Lstar_N = (
normalised_achromatic_lightness_correlate(B_r,
brightness_ideal_white))
# -------------------------------------------------------------------------
# Computing the *hue* angle :math:`\\theta`.
# -------------------------------------------------------------------------
theta = hue_angle(p_response, t_response)
# TODO: Implement hue quadrature & composition computation.
# -------------------------------------------------------------------------
# Computing the correlate of *saturation* :math:`S`.
# -------------------------------------------------------------------------
S_RG, S_YB = saturation_components(theta, bL_or,
t_response,
p_response)
S = saturation_correlate(S_RG, S_YB)
# -------------------------------------------------------------------------
# Computing the correlate of *chroma* :math:`C`.
# -------------------------------------------------------------------------
C_RG, C_YB = chroma_components(Lstar_P, S_RG, S_YB)
C = chroma_correlate(Lstar_P, S)
# -------------------------------------------------------------------------
# Computing the correlate of *colourfulness* :math:`M`.
# -------------------------------------------------------------------------
# TODO: Investigate components usage.
# M_RG, M_YB = colourfulness_components(C_RG, C_YB,
# brightness_ideal_white)
M = colourfulness_correlate(C, brightness_ideal_white)
return Nayatani95_Specification(Lstar_P,
C,
theta,
S,
B_r,
M,
None,
None,
Lstar_N)
Property for **self.__y** private attribute.
Returns
-------
array_like
self.__y
"""
return self.__y
@y.setter
def y(self, value):
"""
Setter for **self.__y** private attribute.
Parameters
----------
value : array_like
Attribute value.
"""
raise AttributeError('"{0}" attribute is read only!'.format('y'))
else:
warning(('"scipy.interpolate.PchipInterpolator" and '
'"scipy.interpolate.interp1d" interpolators are not available, '
'using "LinearInterpolator" instead!'))
PchipInterpolator = CubicSplineInterpolator = LinearInterpolator
def chromatic_adaptation_CIE1994(XYZ_1,
xy_o1,
xy_o2,
Y_o,
E_o1,
E_o2,
n=1):
"""
Adapts given stimulus *CIE XYZ_1* tristimulus values from test viewing
conditions to reference viewing conditions using CIE 1994 chromatic
adaptation model.
Parameters
----------
XYZ : array_like
*CIE XYZ* tristimulus values of test sample / stimulus in domain
[0, 100].
xy_o1 : array_like
Chromaticity coordinates :math:`x_{o1}` and :math:`y_{o1}` of test
illuminant and background.
xy_o2 : array_like
Chromaticity coordinates :math:`x_{o2}` and :math:`y_{o2}` of reference
illuminant and background.
Y_o : numeric
Luminance factor :math:`Y_o` of achromatic background as percentage in
domain [18, 100].
E_o1 : numeric
Test illuminance :math:`E_{o1}` in :math:`cd/m^2`.
E_o2 : numeric
Reference illuminance :math:`E_{o2}` in :math:`cd/m^2`.
n : numeric, optional
Noise component in fundamental primary system.
Returns
-------
ndarray
Adapted *CIE XYZ_2* tristimulus values of test stimulus.
Warning
-------
The input domain of that definition is non standard!
Notes
-----
- Input *CIE XYZ_1* tristimulus values are in domain [0, 100].
- Output *CIE XYZ_2* tristimulus values are in domain [0, 100].
Examples
--------
>>> XYZ_1 = np.array([28.00, 21.26, 5.27])
>>> xy_o1 = np.array([0.4476, 0.4074])
>>> xy_o2 = np.array([0.3127, 0.3290])
>>> Y_o = 20
>>> E_o1 = 1000
>>> E_o2 = 1000
>>> chromatic_adaptation_CIE1994(XYZ_1, xy_o1, xy_o2, Y_o, E_o1, E_o2) # noqa # doctest: +ELLIPSIS
array([ 24.0337952..., 21.1562121..., 17.6430119...])
"""
Y_o = np.asarray(Y_o)
E_o1 = np.asarray(E_o1)
E_o2 = np.asarray(E_o2)
if np.any(Y_o < 18) or np.any(Y_o > 100):
warning(('"Y_o" luminance factor must be in [18, 100] domain, '
'unpredictable results may occur!'))
RGB_1 = XYZ_to_RGB_cie1994(XYZ_1)
xez_1 = intermediate_values(xy_o1)
xez_2 = intermediate_values(xy_o2)
RGB_o1 = effective_adapting_responses(xez_1, Y_o, E_o1)
RGB_o2 = effective_adapting_responses(xez_2, Y_o, E_o2)
bRGB_o1 = exponential_factors(RGB_o1)
bRGB_o2 = exponential_factors(RGB_o2)
K = K_coefficient(xez_1, xez_2, bRGB_o1, bRGB_o2, Y_o, n)
RGB_2 = corresponding_colour(
RGB_1, xez_1, xez_2, bRGB_o1, bRGB_o2, Y_o, K, n)
XYZ_2 = RGB_to_XYZ_cie1994(RGB_2)
return XYZ_2