def test_n_dimensional_intermediate_luminance_function_CIE1976(self):
"""
Tests :func:`colour.colorimetry.luminance.\
intermediate_luminance_function_CIE1976` definition n-dimensional arrays
support.
"""
f_Y_Y_n = 0.495929964178047
Y = 12.197225350000002
np.testing.assert_almost_equal(
intermediate_luminance_function_CIE1976(f_Y_Y_n), Y, decimal=7)
f_Y_Y_n = np.tile(f_Y_Y_n, 6)
Y = np.tile(Y, 6)
np.testing.assert_almost_equal(
intermediate_luminance_function_CIE1976(f_Y_Y_n), Y, decimal=7)
f_Y_Y_n = np.reshape(f_Y_Y_n, (2, 3))
Y = np.reshape(Y, (2, 3))
np.testing.assert_almost_equal(
intermediate_luminance_function_CIE1976(f_Y_Y_n), Y, decimal=7)
f_Y_Y_n = np.reshape(f_Y_Y_n, (2, 3, 1))
Y = np.reshape(Y, (2, 3, 1))
np.testing.assert_almost_equal(
intermediate_luminance_function_CIE1976(f_Y_Y_n), Y, decimal=7)
def test_nan_intermediate_luminance_function_CIE1976(self):
"""
Tests :func:`colour.colorimetry.luminance.\
intermediate_luminance_function_CIE1976` definition nan support.
"""
intermediate_luminance_function_CIE1976(
np.array([-1.0, 0.0, 1.0, -np.inf, np.inf, np.nan]))
def test_nan_intermediate_luminance_function_CIE1976(self):
"""
Test :func:`colour.colorimetry.luminance.\
intermediate_luminance_function_CIE1976` definition nan support.
"""
intermediate_luminance_function_CIE1976(
np.array([-1.0, 0.0, 1.0, -np.inf, np.inf, np.nan]))
def test_domain_range_scale_intermediate_luminance_function_CIE1976(self):
"""
Tests :func:`colour.colorimetry.luminance.\
intermediate_luminance_function_CIE1976` definition domain and range scale
support.
"""
Y = intermediate_luminance_function_CIE1976(41.527875844653451, 100)
for scale in ('reference', 1, 100):
with domain_range_scale(scale):
np.testing.assert_almost_equal(
intermediate_luminance_function_CIE1976(
41.527875844653451, 100),
Y,
decimal=7)
def test_domain_range_scale_intermediate_luminance_function_CIE1976(self):
"""
Tests :func:`colour.colorimetry.luminance.\
intermediate_luminance_function_CIE1976` definition domain and range scale
support.
"""
Y = intermediate_luminance_function_CIE1976(41.527875844653451, 100)
for scale in ('reference', 1, 100):
with domain_range_scale(scale):
np.testing.assert_almost_equal(
intermediate_luminance_function_CIE1976(
41.527875844653451, 100),
Y,
decimal=7)
def test_intermediate_luminance_function_CIE1976(self):
"""
Tests :func:`colour.colorimetry.luminance.\
intermediate_luminance_function_CIE1976` definition.
"""
self.assertAlmostEqual(
intermediate_luminance_function_CIE1976(0.495929964178047),
12.197225350000002,
places=7)
self.assertAlmostEqual(
intermediate_luminance_function_CIE1976(0.613072093530391),
23.042767810000004,
places=7)
self.assertAlmostEqual(
intermediate_luminance_function_CIE1976(0.394876333449113),
6.157200790000001,
places=7)
def test_intermediate_luminance_function_CIE1976(self):
"""
Tests :func:`colour.colorimetry.luminance.\
intermediate_luminance_function_CIE1976` definition.
"""
self.assertAlmostEqual(
intermediate_luminance_function_CIE1976(0.495929964178047),
12.197225350000002,
places=7)
self.assertAlmostEqual(
intermediate_luminance_function_CIE1976(0.613072093530391),
23.042767810000004,
places=7)
self.assertAlmostEqual(
intermediate_luminance_function_CIE1976(0.394876333449113),
6.157200790000001,
places=7)
def test_n_dimensional_intermediate_luminance_function_CIE1976(self):
"""
Tests :func:`colour.colorimetry.luminance.\
intermediate_luminance_function_CIE1976` definition n-dimensional arrays
support.
"""
f_Y_Y_n = 0.495929964178047
Y = intermediate_luminance_function_CIE1976(f_Y_Y_n)
f_Y_Y_n = np.tile(f_Y_Y_n, 6)
Y = np.tile(Y, 6)
np.testing.assert_almost_equal(
intermediate_luminance_function_CIE1976(f_Y_Y_n), Y, decimal=7)
f_Y_Y_n = np.reshape(f_Y_Y_n, (2, 3))
Y = np.reshape(Y, (2, 3))
np.testing.assert_almost_equal(
intermediate_luminance_function_CIE1976(f_Y_Y_n), Y, decimal=7)
f_Y_Y_n = np.reshape(f_Y_Y_n, (2, 3, 1))
Y = np.reshape(Y, (2, 3, 1))
np.testing.assert_almost_equal(
intermediate_luminance_function_CIE1976(f_Y_Y_n), Y, decimal=7)
def Lab_to_XYZ(
Lab,
illuminant=ILLUMINANTS['CIE 1931 2 Degree Standard Observer']['D65']):
"""
Converts from *CIE L\\*a\\*b\\** colourspace to *CIE XYZ* tristimulus
values.
Parameters
----------
Lab : array_like
*CIE L\\*a\\*b\\** colourspace array.
illuminant : array_like, optional
Reference *illuminant* *CIE xy* chromaticity coordinates or *CIE xyY*
colourspace array.
Returns
-------
ndarray
*CIE XYZ* tristimulus values.
Notes
-----
+----------------+-----------------------+-----------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+================+=======================+=================+
| ``Lab`` | ``L`` : [0, 100] | ``L`` : [0, 1] |
| | | |
| | ``a`` : [-100, 100] | ``a`` : [-1, 1] |
| | | |
| | ``b`` : [-100, 100] | ``b`` : [-1, 1] |
+----------------+-----------------------+-----------------+
| ``illuminant`` | [0, 1] | [0, 1] |
+----------------+-----------------------+-----------------+
+----------------+-----------------------+-----------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+================+=======================+=================+
| ``XYZ`` | [0, 1] | [0, 1] |
+----------------+-----------------------+-----------------+
References
----------
:cite:`CIETC1-482004m`
Examples
--------
>>> import numpy as np
>>> Lab = np.array([41.52787529, 52.63858304, 26.92317922])
>>> Lab_to_XYZ(Lab) # doctest: +ELLIPSIS
array([ 0.2065400..., 0.1219722..., 0.0513695...])
"""
L, a, b = tsplit(to_domain_100(Lab))
X_n, Y_n, Z_n = tsplit(xyY_to_XYZ(xy_to_xyY(illuminant)))
f_Y_Y_n = (L + 16) / 116
f_X_X_n = a / 500 + f_Y_Y_n
f_Z_Z_n = f_Y_Y_n - b / 200
X = intermediate_luminance_function_CIE1976(f_X_X_n, X_n)
Y = intermediate_luminance_function_CIE1976(f_Y_Y_n, Y_n)
Z = intermediate_luminance_function_CIE1976(f_Z_Z_n, Z_n)
XYZ = tstack([X, Y, Z])
return from_range_1(XYZ)
def Lab_to_XYZ(
Lab,
illuminant=ILLUMINANTS['CIE 1931 2 Degree Standard Observer']['D65']):
"""
Converts from *CIE L\\*a\\*b\\** colourspace to *CIE XYZ* tristimulus
values.
Parameters
----------
Lab : array_like
*CIE L\\*a\\*b\\** 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** |
+================+=======================+=================+
| ``Lab`` | ``L`` : [0, 100] | ``L`` : [0, 1] |
| | | |
| | ``a`` : [-100, 100] | ``a`` : [-1, 1] |
| | | |
| | ``b`` : [-100, 100] | ``b`` : [-1, 1] |
+----------------+-----------------------+-----------------+
| ``illuminant`` | [0, 1] | [0, 1] |
+----------------+-----------------------+-----------------+
+----------------+-----------------------+-----------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+================+=======================+=================+
| ``XYZ`` | [0, 1] | [0, 1] |
+----------------+-----------------------+-----------------+
References
----------
:cite:`CIETC1-482004m`
Examples
--------
>>> Lab = np.array([41.52787529, 52.63858304, 26.92317922])
>>> Lab_to_XYZ(Lab) # doctest: +ELLIPSIS
array([ 0.2065400..., 0.1219722..., 0.0513695...])
"""
L, a, b = tsplit(to_domain_100(Lab))
X_n, Y_n, Z_n = tsplit(xyY_to_XYZ(xy_to_xyY(illuminant)))
f_Y_Y_n = (L + 16) / 116
f_X_X_n = a / 500 + f_Y_Y_n
f_Z_Z_n = f_Y_Y_n - b / 200
X = intermediate_luminance_function_CIE1976(f_X_X_n, X_n)
Y = intermediate_luminance_function_CIE1976(f_Y_Y_n, Y_n)
Z = intermediate_luminance_function_CIE1976(f_Z_Z_n, Z_n)
XYZ = tstack([X, Y, Z])
return from_range_1(XYZ)
