Files
scikit-image/skimage/segmentation/tests/test_active_contour_model.py
2016-07-21 19:11:28 -04:00

117 lines
4.6 KiB
Python

import numpy as np
from skimage import data
from skimage.color import rgb2gray
from skimage.filters import gaussian
from skimage.segmentation import active_contour
from numpy.testing import assert_equal, assert_allclose, assert_raises
from numpy.testing.decorators import skipif
import scipy
scipy_version = list(map(int, scipy.__version__.split('.')))
new_scipy = scipy_version[0] > 0 or \
(scipy_version[0] == 0 and scipy_version[1] >= 14)
@skipif(not new_scipy)
def test_periodic_reference():
img = data.astronaut()
img = rgb2gray(img)
s = np.linspace(0, 2*np.pi, 400)
x = 220 + 100*np.cos(s)
y = 100 + 100*np.sin(s)
init = np.array([x, y]).T
snake = active_contour(gaussian(img, 3), init,
alpha=0.015, beta=10, w_line=0, w_edge=1, gamma=0.001)
refx = [299, 298, 298, 298, 298, 297, 297, 296, 296, 295]
refy = [98, 99, 100, 101, 102, 103, 104, 105, 106, 108]
assert_equal(np.array(snake[:10, 0], dtype=np.int32), refx)
assert_equal(np.array(snake[:10, 1], dtype=np.int32), refy)
@skipif(not new_scipy)
def test_fixed_reference():
img = data.text()
x = np.linspace(5, 424, 100)
y = np.linspace(136, 50, 100)
init = np.array([x, y]).T
snake = active_contour(gaussian(img, 1), init, bc='fixed',
alpha=0.1, beta=1.0, w_line=-5, w_edge=0, gamma=0.1)
refx = [5, 9, 13, 17, 21, 25, 30, 34, 38, 42]
refy = [136, 135, 134, 133, 132, 131, 129, 128, 127, 125]
assert_equal(np.array(snake[:10, 0], dtype=np.int32), refx)
assert_equal(np.array(snake[:10, 1], dtype=np.int32), refy)
@skipif(not new_scipy)
def test_free_reference():
img = data.text()
x = np.linspace(5, 424, 100)
y = np.linspace(70, 40, 100)
init = np.array([x, y]).T
snake = active_contour(gaussian(img, 3), init, bc='free',
alpha=0.1, beta=1.0, w_line=-5, w_edge=0, gamma=0.1)
refx = [10, 13, 16, 19, 23, 26, 29, 32, 36, 39]
refy = [76, 76, 75, 74, 73, 72, 71, 70, 69, 69]
assert_equal(np.array(snake[:10, 0], dtype=np.int32), refx)
assert_equal(np.array(snake[:10, 1], dtype=np.int32), refy)
@skipif(not new_scipy)
def test_RGB():
img = gaussian(data.text(), 1)
imgR = np.zeros((img.shape[0], img.shape[1], 3))
imgG = np.zeros((img.shape[0], img.shape[1], 3))
imgRGB = np.zeros((img.shape[0], img.shape[1], 3))
imgR[:, :, 0] = img
imgG[:, :, 1] = img
imgRGB[:, :, :] = img[:, :, None]
x = np.linspace(5, 424, 100)
y = np.linspace(136, 50, 100)
init = np.array([x, y]).T
snake = active_contour(imgR, init, bc='fixed',
alpha=0.1, beta=1.0, w_line=-5, w_edge=0, gamma=0.1)
refx = [5, 9, 13, 17, 21, 25, 30, 34, 38, 42]
refy = [136, 135, 134, 133, 132, 131, 129, 128, 127, 125]
assert_equal(np.array(snake[:10, 0], dtype=np.int32), refx)
assert_equal(np.array(snake[:10, 1], dtype=np.int32), refy)
snake = active_contour(imgG, init, bc='fixed',
alpha=0.1, beta=1.0, w_line=-5, w_edge=0, gamma=0.1)
assert_equal(np.array(snake[:10, 0], dtype=np.int32), refx)
assert_equal(np.array(snake[:10, 1], dtype=np.int32), refy)
snake = active_contour(imgRGB, init, bc='fixed',
alpha=0.1, beta=1.0, w_line=-5/3., w_edge=0, gamma=0.1)
assert_equal(np.array(snake[:10, 0], dtype=np.int32), refx)
assert_equal(np.array(snake[:10, 1], dtype=np.int32), refy)
@skipif(not new_scipy)
def test_end_points():
img = data.astronaut()
img = rgb2gray(img)
s = np.linspace(0, 2*np.pi, 400)
x = 220 + 100*np.cos(s)
y = 100 + 100*np.sin(s)
init = np.array([x, y]).T
snake = active_contour(gaussian(img, 3), init,
bc='periodic', alpha=0.015, beta=10, w_line=0, w_edge=1,
gamma=0.001, max_iterations=100)
assert np.sum(np.abs(snake[0, :]-snake[-1, :])) < 2
snake = active_contour(gaussian(img, 3), init,
bc='free', alpha=0.015, beta=10, w_line=0, w_edge=1,
gamma=0.001, max_iterations=100)
assert np.sum(np.abs(snake[0, :]-snake[-1, :])) > 2
snake = active_contour(gaussian(img, 3), init,
bc='fixed', alpha=0.015, beta=10, w_line=0, w_edge=1,
gamma=0.001, max_iterations=100)
assert_allclose(snake[0, :], [x[0], y[0]], atol=1e-5)
@skipif(not new_scipy)
def test_bad_input():
img = np.zeros((10, 10))
x = np.linspace(5, 424, 100)
y = np.linspace(136, 50, 100)
init = np.array([x, y]).T
assert_raises(ValueError, active_contour, img, init,
bc='wrong')
assert_raises(ValueError, active_contour, img, init,
max_iterations=-15)
if __name__ == "__main__":
np.testing.run_module_suite()