131 lines
5.5 KiB
Python
131 lines
5.5 KiB
Python
import numpy as np
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from skimage import data
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from skimage.color import rgb2gray
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from skimage.filters import gaussian
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from skimage.segmentation import active_contour
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from skimage._shared import testing
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from skimage._shared.testing import assert_equal, assert_allclose
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def test_periodic_reference():
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img = data.astronaut()
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img = rgb2gray(img)
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s = np.linspace(0, 2*np.pi, 400)
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r = 100 + 100*np.sin(s)
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c = 220 + 100*np.cos(s)
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init = np.array([r, c]).T
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snake = active_contour(gaussian(img, 3), init, alpha=0.015, beta=10,
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w_line=0, w_edge=1, gamma=0.001)
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refr = [98, 99, 100, 101, 102, 103, 104, 105, 106, 108]
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refc = [299, 298, 298, 298, 298, 297, 297, 296, 296, 295]
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assert_equal(np.array(snake[:10, 0], dtype=np.int32), refr)
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assert_equal(np.array(snake[:10, 1], dtype=np.int32), refc)
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def test_fixed_reference():
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img = data.text()
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r = np.linspace(136, 50, 100)
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c = np.linspace(5, 424, 100)
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init = np.array([r, c]).T
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snake = active_contour(gaussian(img, 1), init, boundary_condition='fixed',
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alpha=0.1, beta=1.0, w_line=-5, w_edge=0, gamma=0.1)
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refr = [136, 135, 134, 133, 132, 131, 129, 128, 127, 125]
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refc = [5, 9, 13, 17, 21, 25, 30, 34, 38, 42]
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assert_equal(np.array(snake[:10, 0], dtype=np.int32), refr)
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assert_equal(np.array(snake[:10, 1], dtype=np.int32), refc)
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def test_free_reference():
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img = data.text()
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r = np.linspace(70, 40, 100)
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c = np.linspace(5, 424, 100)
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init = np.array([r, c]).T
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snake = active_contour(gaussian(img, 3), init, boundary_condition='free',
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alpha=0.1, beta=1.0, w_line=-5, w_edge=0, gamma=0.1)
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refr = [76, 76, 75, 74, 73, 72, 71, 70, 69, 69]
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refc = [10, 13, 16, 19, 23, 26, 29, 32, 36, 39]
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assert_equal(np.array(snake[:10, 0], dtype=np.int32), refr)
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assert_equal(np.array(snake[:10, 1], dtype=np.int32), refc)
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def test_RGB():
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img = gaussian(data.text(), 1)
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imgR = np.zeros((img.shape[0], img.shape[1], 3))
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imgG = np.zeros((img.shape[0], img.shape[1], 3))
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imgRGB = np.zeros((img.shape[0], img.shape[1], 3))
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imgR[:, :, 0] = img
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imgG[:, :, 1] = img
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imgRGB[:, :, :] = img[:, :, None]
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r = np.linspace(136, 50, 100)
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c = np.linspace(5, 424, 100)
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init = np.array([r, c]).T
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snake = active_contour(imgR, init, boundary_condition='fixed',
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alpha=0.1, beta=1.0, w_line=-5, w_edge=0, gamma=0.1)
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refr = [136, 135, 134, 133, 132, 131, 129, 128, 127, 125]
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refc = [5, 9, 13, 17, 21, 25, 30, 34, 38, 42]
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assert_equal(np.array(snake[:10, 0], dtype=np.int32), refr)
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assert_equal(np.array(snake[:10, 1], dtype=np.int32), refc)
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snake = active_contour(imgG, init, boundary_condition='fixed',
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alpha=0.1, beta=1.0, w_line=-5, w_edge=0, gamma=0.1)
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assert_equal(np.array(snake[:10, 0], dtype=np.int32), refr)
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assert_equal(np.array(snake[:10, 1], dtype=np.int32), refc)
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snake = active_contour(imgRGB, init, boundary_condition='fixed',
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alpha=0.1, beta=1.0, w_line=-5/3., w_edge=0,
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gamma=0.1)
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assert_equal(np.array(snake[:10, 0], dtype=np.int32), refr)
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assert_equal(np.array(snake[:10, 1], dtype=np.int32), refc)
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def test_end_points():
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img = data.astronaut()
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img = rgb2gray(img)
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s = np.linspace(0, 2*np.pi, 400)
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r = 100 + 100*np.sin(s)
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c = 220 + 100*np.cos(s)
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init = np.array([r, c]).T
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snake = active_contour(gaussian(img, 3), init,
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boundary_condition='periodic', alpha=0.015, beta=10,
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w_line=0, w_edge=1, gamma=0.001, max_iterations=100)
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assert np.sum(np.abs(snake[0, :]-snake[-1, :])) < 2
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snake = active_contour(gaussian(img, 3), init,
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boundary_condition='free', alpha=0.015, beta=10,
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w_line=0, w_edge=1, gamma=0.001, max_iterations=100)
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assert np.sum(np.abs(snake[0, :]-snake[-1, :])) > 2
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snake = active_contour(gaussian(img, 3), init,
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boundary_condition='fixed', alpha=0.015, beta=10,
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w_line=0, w_edge=1, gamma=0.001, max_iterations=100)
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assert_allclose(snake[0, :], [r[0], c[0]], atol=1e-5)
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def test_bad_input():
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img = np.zeros((10, 10))
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r = np.linspace(136, 50, 100)
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c = np.linspace(5, 424, 100)
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init = np.array([r, c]).T
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with testing.raises(ValueError):
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active_contour(img, init, boundary_condition='wrong')
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with testing.raises(ValueError):
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active_contour(img, init, max_iterations=-15)
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def test_coord_raises():
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img = rgb2gray(data.astronaut())
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s = np.linspace(0, 2*np.pi, 400)
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x = 100 + 100*np.sin(s)
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y = 220 + 100*np.cos(s)
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init = np.array([x, y]).T
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# coordinates='xy' is not valid
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with testing.raises(ValueError):
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snake = active_contour(gaussian(img, 3), init,
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boundary_condition='periodic', alpha=0.015,
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beta=10, w_line=0, w_edge=1, gamma=0.001,
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max_iterations=100, coordinates='xy')
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# coordinates=None is not valid
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with testing.raises(ValueError):
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snake = active_contour(gaussian(img, 3), init,
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boundary_condition='periodic', alpha=0.015,
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beta=10, w_line=0, w_edge=1, gamma=0.001,
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max_iterations=100, coordinates=None)
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