def test_rgb_lch_roundtrip(self):
rgb = img_as_float(self.img_rgb)
lab = rgb2lab(rgb)
lch = lab2lch(lab)
lab2 = lch2lab(lch)
rgb2 = lab2rgb(lab2)
assert_array_almost_equal(rgb, rgb2)
def test_rgb2lab_brucelindbloom(self):
"""
Test the RGB->Lab conversion by comparing to the calculator on the
authoritative Bruce Lindbloom
[website](http://brucelindbloom.com/index.html?ColorCalculator.html).
"""
# Obtained with D65 white point, sRGB model and gamma
# ftm: off
gt_for_colbars = cp.asarray([
[100, 0, 0],
[97.1393, -21.5537, 94.4780],
[91.1132, -48.0875, -14.1312],
[87.7347, -86.1827, 83.1793],
[60.3242, 98.2343, -60.8249],
[53.2408, 80.0925, 67.2032],
[32.2970, 79.1875, -107.8602],
[0, 0, 0]]).T
# ftm: on
gt_array = cp.swapaxes(gt_for_colbars.reshape(3, 4, 2), 0, 2)
assert_array_almost_equal(rgb2lab(self.colbars_array), gt_array,
decimal=2)
def _get_lab0(self):
rgb = img_as_float(self.img_rgb[:1, :1, :])
return rgb2lab(rgb)[0, 0, :]
def test_lab_lch_roundtrip(self):
rgb = img_as_float(self.img_rgb)
lab = rgb2lab(rgb)
lab2 = lch2lab(lab2lch(lab))
assert_array_almost_equal(lab2, lab)
def test_rgb2lab_dtype(self):
img = self.colbars_array.astype('float64')
img32 = img.astype('float32')
assert rgb2lab(img).dtype == img.dtype
assert rgb2lab(img32).dtype == img32.dtype
def test_lab_rgb_roundtrip(self):
img_rgb = img_as_float(self.img_rgb)
assert_array_almost_equal(lab2rgb(rgb2lab(img_rgb)), img_rgb)