def test_nan_luminance_CIE1976(self):
"""
Test :func:`colour.colorimetry.luminance.luminance_CIE1976`
definition nan support.
"""
luminance_CIE1976(np.array([-1.0, 0.0, 1.0, -np.inf, np.inf, np.nan]))
def test_nan_luminance_CIE1976(self):
"""
Tests :func:`colour.colorimetry.luminance.luminance_CIE1976`
definition nan support.
"""
luminance_CIE1976(np.array([-1.0, 0.0, 1.0, -np.inf, np.inf, np.nan]))
def test_domain_range_scale_luminance_CIE1976(self):
"""
Tests :func:`colour.colorimetry.luminance.luminance_CIE1976`
definition domain and range scale support.
"""
Y = luminance_CIE1976(41.527875844653451, 100)
d_r = (('reference', 1), (1, 0.01), (100, 1))
for scale, factor in d_r:
with domain_range_scale(scale):
np.testing.assert_almost_equal(
luminance_CIE1976(41.527875844653451 * factor, 100),
Y * factor,
decimal=7)
def test_domain_range_scale_luminance_CIE1976(self):
"""
Tests :func:`colour.colorimetry.luminance.luminance_CIE1976`
definition domain and range scale support.
"""
Y = luminance_CIE1976(41.527875844653451, 100)
d_r = (('reference', 1), (1, 0.01), (100, 1))
for scale, factor in d_r:
with domain_range_scale(scale):
np.testing.assert_almost_equal(luminance_CIE1976(
41.527875844653451 * factor, 100),
Y * factor,
decimal=7)
def test_n_dimensional_luminance_CIE1976(self):
"""
Tests :func:`colour.colorimetry.luminance.luminance_CIE1976`
definition n-dimensional arrays support.
"""
L_star = 41.527875844653451
Y = luminance_CIE1976(L_star)
L_star = np.tile(L_star, 6)
Y = np.tile(Y, 6)
np.testing.assert_almost_equal(luminance_CIE1976(L_star), Y, decimal=7)
L_star = np.reshape(L_star, (2, 3))
Y = np.reshape(Y, (2, 3))
np.testing.assert_almost_equal(luminance_CIE1976(L_star), Y, decimal=7)
L_star = np.reshape(L_star, (2, 3, 1))
Y = np.reshape(Y, (2, 3, 1))
np.testing.assert_almost_equal(luminance_CIE1976(L_star), Y, decimal=7)
def test_n_dimensional_luminance_CIE1976(self):
"""
Test :func:`colour.colorimetry.luminance.luminance_CIE1976`
definition n-dimensional arrays support.
"""
L_star = 41.527875844653451
Y = luminance_CIE1976(L_star)
L_star = np.tile(L_star, 6)
Y = np.tile(Y, 6)
np.testing.assert_almost_equal(luminance_CIE1976(L_star), Y, decimal=7)
L_star = np.reshape(L_star, (2, 3))
Y = np.reshape(Y, (2, 3))
np.testing.assert_almost_equal(luminance_CIE1976(L_star), Y, decimal=7)
L_star = np.reshape(L_star, (2, 3, 1))
Y = np.reshape(Y, (2, 3, 1))
np.testing.assert_almost_equal(luminance_CIE1976(L_star), Y, decimal=7)
def test_luminance_CIE1976(self):
"""
Tests :func:`colour.colorimetry.luminance.luminance_CIE1976`
definition.
"""
self.assertAlmostEqual(
luminance_CIE1976(41.527875844653451),
12.197225350000002,
places=7)
self.assertAlmostEqual(
luminance_CIE1976(55.116362849525402),
23.042767810000004,
places=7)
self.assertAlmostEqual(
luminance_CIE1976(29.805654680097106), 6.157200790000001, places=7)
self.assertAlmostEqual(
luminance_CIE1976(56.480581732417676, 50),
12.197225349999998,
places=7)
self.assertAlmostEqual(
luminance_CIE1976(47.317620274162735, 75),
12.197225350000002,
places=7)
self.assertAlmostEqual(
luminance_CIE1976(42.519930728120940, 95),
12.197225350000005,
places=7)
def test_luminance_CIE1976(self):
"""
Test :func:`colour.colorimetry.luminance.luminance_CIE1976`
definition.
"""
self.assertAlmostEqual(luminance_CIE1976(41.527875844653451),
12.197225350000002,
places=7)
self.assertAlmostEqual(luminance_CIE1976(55.116362849525402),
23.042767810000004,
places=7)
self.assertAlmostEqual(luminance_CIE1976(29.805654680097106),
6.157200790000001,
places=7)
self.assertAlmostEqual(
luminance_CIE1976(56.480581732417676, 50),
12.197225349999998,
places=7,
)
self.assertAlmostEqual(
luminance_CIE1976(47.317620274162735, 75),
12.197225350000002,
places=7,
)
self.assertAlmostEqual(
luminance_CIE1976(42.519930728120940, 95),
12.197225350000005,
places=7,
)
def Luv_to_XYZ(
Luv,
illuminant=ILLUMINANTS['CIE 1931 2 Degree Standard Observer']['D65']):
"""
Converts from *CIE L\\*u\\*v\\** colourspace to *CIE XYZ* tristimulus
values.
Parameters
----------
Luv : array_like
*CIE L\\*u\\*v\\** colourspace array.
illuminant : array_like, optional
Reference *illuminant* *xy* chromaticity coordinates or *CIE xyY*
colourspace array.
Returns
-------
ndarray
*CIE XYZ* tristimulus values.
Notes
-----
+----------------+-----------------------+-----------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+================+=======================+=================+
| ``Luv`` | ``L`` : [0, 100] | ``L`` : [0, 1] |
| | | |
| | ``u`` : [-100, 100] | ``u`` : [-1, 1] |
| | | |
| | ``v`` : [-100, 100] | ``v`` : [-1, 1] |
+----------------+-----------------------+-----------------+
| ``illuminant`` | [0, 1] | [0, 1] |
+----------------+-----------------------+-----------------+
+----------------+-----------------------+-----------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+================+=======================+=================+
| ``XYZ`` | [0, 1] | [0, 1] |
+----------------+-----------------------+-----------------+
References
----------
:cite:`CIETC1-482004m`, :cite:`Wikipedia2007b`
Examples
--------
>>> Luv = np.array([41.52787529, 96.83626054, 17.75210149])
>>> Luv_to_XYZ(Luv) # doctest: +ELLIPSIS
array([ 0.2065400..., 0.1219722..., 0.0513695...])
"""
L, u, v = tsplit(to_domain_100(Luv))
X_r, Y_r, Z_r = tsplit(xyY_to_XYZ(xy_to_xyY(illuminant)))
with domain_range_scale('100'):
Y = luminance_CIE1976(L, Y_r)
a = 1 / 3 * ((52 * L / (u + 13 * L * (4 * X_r /
(X_r + 15 * Y_r + 3 * Z_r)))) - 1)
b = -5 * Y
c = -1 / 3.0
d = Y * (39 * L / (v + 13 * L * (9 * Y_r /
(X_r + 15 * Y_r + 3 * Z_r))) - 5)
X = (d - b) / (a - c)
Z = X * a + b
XYZ = tstack([X, Y, Z])
return from_range_1(XYZ)
def Luv_to_XYZ(
Luv,
illuminant=ILLUMINANTS['CIE 1931 2 Degree Standard Observer']['D65']):
"""
Converts from *CIE L\\*u\\*v\\** colourspace to *CIE XYZ* tristimulus
values.
Parameters
----------
Luv : array_like
*CIE L\\*u\\*v\\** colourspace array.
illuminant : array_like, optional
Reference *illuminant* *xy* chromaticity coordinates or *CIE xyY*
colourspace array.
Returns
-------
ndarray
*CIE XYZ* tristimulus values.
Notes
-----
+----------------+-----------------------+-----------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+================+=======================+=================+
| ``Luv`` | ``L`` : [0, 100] | ``L`` : [0, 1] |
| | | |
| | ``u`` : [-100, 100] | ``u`` : [-1, 1] |
| | | |
| | ``v`` : [-100, 100] | ``v`` : [-1, 1] |
+----------------+-----------------------+-----------------+
| ``illuminant`` | [0, 1] | [0, 1] |
+----------------+-----------------------+-----------------+
+----------------+-----------------------+-----------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+================+=======================+=================+
| ``XYZ`` | [0, 1] | [0, 1] |
+----------------+-----------------------+-----------------+
References
----------
:cite:`CIETC1-482004m`, :cite:`Wikipedia2007b`
Examples
--------
>>> Luv = np.array([41.52787529, 96.83626054, 17.75210149])
>>> Luv_to_XYZ(Luv) # doctest: +ELLIPSIS
array([ 0.2065400..., 0.1219722..., 0.0513695...])
"""
L, u, v = tsplit(to_domain_100(Luv))
X_r, Y_r, Z_r = tsplit(xyY_to_XYZ(xy_to_xyY(illuminant)))
with domain_range_scale('100'):
Y = luminance_CIE1976(L, Y_r)
a = 1 / 3 * (
(52 * L / (u + 13 * L * (4 * X_r / (X_r + 15 * Y_r + 3 * Z_r)))) - 1)
b = -5 * Y
c = -1 / 3.0
d = Y * (39 * L / (v + 13 * L * (9 * Y_r /
(X_r + 15 * Y_r + 3 * Z_r))) - 5)
X = (d - b) / (a - c)
Z = X * a + b
XYZ = tstack([X, Y, Z])
return from_range_1(XYZ)
