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MLPproject/.venv/lib/python3.12/site-packages/skimage/segmentation/tests/test_quickshift.py
2025-10-23 15:44:32 +02:00

80 lines
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Python

import numpy as np
import pytest
from skimage.segmentation import quickshift
from skimage._shared import testing
from skimage._shared.testing import (
assert_greater,
run_in_parallel,
assert_equal,
assert_array_equal,
)
@run_in_parallel()
@testing.parametrize('dtype', [np.float32, np.float64])
def test_grey(dtype):
rng = np.random.default_rng(0)
img = np.zeros((20, 21))
img[:10, 10:] = 0.2
img[10:, :10] = 0.4
img[10:, 10:] = 0.6
img += 0.05 * rng.normal(size=img.shape)
img = img.astype(dtype, copy=False)
seg = quickshift(img, kernel_size=2, max_dist=3, rng=0, convert2lab=False, sigma=0)
quickshift(img, kernel_size=2, max_dist=3, rng=0, convert2lab=False, sigma=0)
# we expect 4 segments:
assert_equal(len(np.unique(seg)), 4)
# that mostly respect the 4 regions:
for i in range(4):
hist = np.histogram(img[seg == i], bins=[0, 0.1, 0.3, 0.5, 1])[0]
assert_greater(hist[i], 20)
@testing.parametrize('dtype', [np.float32, np.float64])
@testing.parametrize('channel_axis', [-3, -2, -1, 0, 1, 2])
def test_color(dtype, channel_axis):
rng = np.random.default_rng(583428449)
img = np.zeros((20, 21, 3))
img[:10, :10, 0] = 1
img[10:, :10, 1] = 1
img[10:, 10:, 2] = 1
img += 0.01 * rng.normal(size=img.shape)
img[img > 1] = 1
img[img < 0] = 0
img = img.astype(dtype, copy=False)
img = np.moveaxis(img, source=-1, destination=channel_axis)
seg = quickshift(
img, rng=0, max_dist=30, kernel_size=10, sigma=0, channel_axis=channel_axis
)
# we expect 4 segments:
assert_equal(len(np.unique(seg)), 4)
assert_array_equal(seg[:10, :10], 1)
assert_array_equal(seg[10:, :10], 3)
assert_array_equal(seg[:10, 10:], 0)
assert_array_equal(seg[10:, 10:], 2)
seg2 = quickshift(
img,
kernel_size=1,
max_dist=2,
rng=0,
convert2lab=False,
sigma=0,
channel_axis=channel_axis,
)
# very oversegmented:
assert len(np.unique(seg2)) > 10
# still don't cross lines
assert (seg2[9, :] != seg2[10, :]).all()
assert (seg2[:, 9] != seg2[:, 10]).all()
def test_convert2lab_not_rgb():
img = np.zeros((20, 21, 2))
with pytest.raises(
ValueError, match="Only RGB images can be converted to Lab space"
):
quickshift(img, convert2lab=True)