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scikit-image/skimage/segmentation/tests/test_slic.py
T
Juan Nunez-Iglesias ea1566fffb Fix image dimension sanitizing at function start
`np.atleast_3d` will add a singleton dimension at the end of an array
if needed. This is not the correct thing to do if `multichannel=False`
based on the subsequent lines. If the input image was 2D with shape
`(40, 50)` and `multichannel=False`, then `np.atleast_3d` gives it
shape `(40, 50, 1)`, and then, because `multichannel=False`, the rest
of the code gives it shape `(40, 50, 1, 1)`. This results in the final
returned array having shape `(40, 50, 1)` instead of the desired
`(40, 50)`.

This commit fixes that and updates the test to detect this failure.
2013-09-16 16:02:24 +10:00

96 lines
2.8 KiB
Python

import itertools as it
import warnings
import numpy as np
from numpy.testing import assert_equal, assert_array_equal
from skimage.segmentation import slic
def test_color_2d():
rnd = np.random.RandomState(0)
img = np.zeros((20, 21, 3))
img[:10, :10, 0] = 1
img[10:, :10, 1] = 1
img[10:, 10:, 2] = 1
img += 0.01 * rnd.normal(size=img.shape)
img[img > 1] = 1
img[img < 0] = 0
with warnings.catch_warnings():
warnings.simplefilter("ignore")
seg = slic(img, n_segments=4, sigma=0)
# we expect 4 segments
assert_equal(len(np.unique(seg)), 4)
assert_equal(seg.shape, img.shape[:-1])
assert_array_equal(seg[:10, :10], 0)
assert_array_equal(seg[10:, :10], 2)
assert_array_equal(seg[:10, 10:], 1)
assert_array_equal(seg[10:, 10:], 3)
def test_gray_2d():
rnd = np.random.RandomState(0)
img = np.zeros((20, 21))
img[:10, :10] = 0.33
img[10:, :10] = 0.67
img[10:, 10:] = 1.00
img += 0.0033 * rnd.normal(size=img.shape)
img[img > 1] = 1
img[img < 0] = 0
seg = slic(img, sigma=0, n_segments=4, compactness=1,
multichannel=False, convert2lab=False)
assert_equal(len(np.unique(seg)), 4)
assert_equal(seg.shape, img.shape)
assert_array_equal(seg[:10, :10], 0)
assert_array_equal(seg[10:, :10], 2)
assert_array_equal(seg[:10, 10:], 1)
assert_array_equal(seg[10:, 10:], 3)
def test_color_3d():
rnd = np.random.RandomState(0)
img = np.zeros((20, 21, 22, 3))
slices = []
for dim_size in img.shape[:-1]:
midpoint = dim_size // 2
slices.append((slice(None, midpoint), slice(midpoint, None)))
slices = list(it.product(*slices))
colors = list(it.product(*(([0, 1],) * 3)))
for s, c in zip(slices, colors):
img[s] = c
img += 0.01 * rnd.normal(size=img.shape)
img[img > 1] = 1
img[img < 0] = 0
seg = slic(img, sigma=0, n_segments=8)
assert_equal(len(np.unique(seg)), 8)
for s, c in zip(slices, range(8)):
assert_array_equal(seg[s], c)
def test_gray_3d():
rnd = np.random.RandomState(0)
img = np.zeros((20, 21, 22))
slices = []
for dim_size in img.shape:
midpoint = dim_size // 2
slices.append((slice(None, midpoint), slice(midpoint, None)))
slices = list(it.product(*slices))
shades = np.arange(0, 1.000001, 1.0/7)
for s, sh in zip(slices, shades):
img[s] = sh
img += 0.001 * rnd.normal(size=img.shape)
img[img > 1] = 1
img[img < 0] = 0
seg = slic(img, sigma=0, n_segments=8, compactness=1,
multichannel=False, convert2lab=False)
assert_equal(len(np.unique(seg)), 8)
for s, c in zip(slices, range(8)):
assert_array_equal(seg[s], c)
if __name__ == '__main__':
from numpy import testing
testing.run_module_suite()