def end_points_tests():
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_model(
gaussian_filter(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_model(
gaussian_filter(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_model(
gaussian_filter(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)
def periodic_reference_test():
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_model(gaussian_filter(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)
def free_reference_test():
img = data.text()
x = np.linspace(5, 424, 100)
y = np.linspace(70, 40, 100)
init = np.array([x, y]).T
snake = active_contour_model(
gaussian_filter(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)
def fixed_reference_test():
img = data.text()
x = np.linspace(5, 424, 100)
y = np.linspace(136, 50, 100)
init = np.array([x, y]).T
snake = active_contour_model(
gaussian_filter(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)
def RGB_test():
img = gaussian_filter(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_model(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_model(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_model(imgRGB, init, bc="fixed", alpha=0.1, beta=1.0, w_line=-5 / 3.0, 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)
