CofeehousePy/deps/scikit-image/skimage/filters/tests/test_edges.py

569 lines
19 KiB
Python

import numpy as np
from skimage import data
from skimage import filters
from skimage.filters.edges import _mask_filter_result
from skimage._shared import testing
from skimage._shared.testing import (assert_array_almost_equal,
assert_, assert_allclose)
def test_roberts_zeros():
"""Roberts' filter on an array of all zeros."""
result = filters.roberts(np.zeros((10, 10)), np.ones((10, 10), bool))
assert (np.all(result == 0))
def test_roberts_diagonal1():
"""Roberts' filter on a diagonal edge should be a diagonal line."""
image = np.tri(10, 10, 0)
expected = ~(np.tri(10, 10, -1).astype(bool) |
np.tri(10, 10, -2).astype(bool).transpose())
expected[-1, -1] = 0 # due to 'reflect' & image shape, last pixel not edge
result = filters.roberts(image).astype(bool)
assert_array_almost_equal(result, expected)
def test_roberts_diagonal2():
"""Roberts' filter on a diagonal edge should be a diagonal line."""
image = np.rot90(np.tri(10, 10, 0), 3)
expected = ~np.rot90(np.tri(10, 10, -1).astype(bool) |
np.tri(10, 10, -2).astype(bool).transpose())
expected = _mask_filter_result(expected, None)
result = filters.roberts(image).astype(bool)
assert_array_almost_equal(result, expected)
def test_sobel_zeros():
"""Sobel on an array of all zeros."""
result = filters.sobel(np.zeros((10, 10)), np.ones((10, 10), bool))
assert (np.all(result == 0))
def test_sobel_mask():
"""Sobel on a masked array should be zero."""
result = filters.sobel(np.random.uniform(size=(10, 10)),
np.zeros((10, 10), dtype=bool))
assert (np.all(result == 0))
def test_sobel_horizontal():
"""Sobel on a horizontal edge should be a horizontal line."""
i, j = np.mgrid[-5:6, -5:6]
image = (i >= 0).astype(float)
result = filters.sobel(image) * np.sqrt(2)
# Check if result match transform direction
assert_allclose(result[i == 0], 1)
assert (np.all(result[np.abs(i) > 1] == 0))
def test_sobel_vertical():
"""Sobel on a vertical edge should be a vertical line."""
i, j = np.mgrid[-5:6, -5:6]
image = (j >= 0).astype(float)
result = filters.sobel(image) * np.sqrt(2)
assert (np.all(result[j == 0] == 1))
assert (np.all(result[np.abs(j) > 1] == 0))
def test_sobel_h_zeros():
"""Horizontal sobel on an array of all zeros."""
result = filters.sobel_h(np.zeros((10, 10)), np.ones((10, 10), dtype=bool))
assert (np.all(result == 0))
def test_sobel_h_mask():
"""Horizontal Sobel on a masked array should be zero."""
result = filters.sobel_h(np.random.uniform(size=(10, 10)),
np.zeros((10, 10), dtype=bool))
assert (np.all(result == 0))
def test_sobel_h_horizontal():
"""Horizontal Sobel on an edge should be a horizontal line."""
i, j = np.mgrid[-5:6, -5:6]
image = (i >= 0).astype(float)
result = filters.sobel_h(image)
# Check if result match transform direction
assert (np.all(result[i == 0] == 1))
assert (np.all(result[np.abs(i) > 1] == 0))
def test_sobel_h_vertical():
"""Horizontal Sobel on a vertical edge should be zero."""
i, j = np.mgrid[-5:6, -5:6]
image = (j >= 0).astype(float) * np.sqrt(2)
result = filters.sobel_h(image)
assert_allclose(result, 0, atol=1e-10)
def test_sobel_v_zeros():
"""Vertical sobel on an array of all zeros."""
result = filters.sobel_v(np.zeros((10, 10)), np.ones((10, 10), dtype=bool))
assert_allclose(result, 0)
def test_sobel_v_mask():
"""Vertical Sobel on a masked array should be zero."""
result = filters.sobel_v(np.random.uniform(size=(10, 10)),
np.zeros((10, 10), dtype=bool))
assert_allclose(result, 0)
def test_sobel_v_vertical():
"""Vertical Sobel on an edge should be a vertical line."""
i, j = np.mgrid[-5:6, -5:6]
image = (j >= 0).astype(float)
result = filters.sobel_v(image)
# Check if result match transform direction
assert (np.all(result[j == 0] == 1))
assert (np.all(result[np.abs(j) > 1] == 0))
def test_sobel_v_horizontal():
"""vertical Sobel on a horizontal edge should be zero."""
i, j = np.mgrid[-5:6, -5:6]
image = (i >= 0).astype(float)
result = filters.sobel_v(image)
assert_allclose(result, 0)
def test_scharr_zeros():
"""Scharr on an array of all zeros."""
result = filters.scharr(np.zeros((10, 10)), np.ones((10, 10), dtype=bool))
assert (np.all(result < 1e-16))
def test_scharr_mask():
"""Scharr on a masked array should be zero."""
result = filters.scharr(np.random.uniform(size=(10, 10)),
np.zeros((10, 10), dtype=bool))
assert_allclose(result, 0)
def test_scharr_horizontal():
"""Scharr on an edge should be a horizontal line."""
i, j = np.mgrid[-5:6, -5:6]
image = (i >= 0).astype(float)
result = filters.scharr(image) * np.sqrt(2)
# Check if result match transform direction
assert_allclose(result[i == 0], 1)
assert (np.all(result[np.abs(i) > 1] == 0))
def test_scharr_vertical():
"""Scharr on a vertical edge should be a vertical line."""
i, j = np.mgrid[-5:6, -5:6]
image = (j >= 0).astype(float)
result = filters.scharr(image) * np.sqrt(2)
assert_allclose(result[j == 0], 1)
assert (np.all(result[np.abs(j) > 1] == 0))
def test_scharr_h_zeros():
"""Horizontal Scharr on an array of all zeros."""
result = filters.scharr_h(np.zeros((10, 10)),
np.ones((10, 10), dtype=bool))
assert_allclose(result, 0)
def test_scharr_h_mask():
"""Horizontal Scharr on a masked array should be zero."""
result = filters.scharr_h(np.random.uniform(size=(10, 10)),
np.zeros((10, 10), dtype=bool))
assert_allclose(result, 0)
def test_scharr_h_horizontal():
"""Horizontal Scharr on an edge should be a horizontal line."""
i, j = np.mgrid[-5:6, -5:6]
image = (i >= 0).astype(float)
result = filters.scharr_h(image)
# Check if result match transform direction
assert (np.all(result[i == 0] == 1))
assert (np.all(result[np.abs(i) > 1] == 0))
def test_scharr_h_vertical():
"""Horizontal Scharr on a vertical edge should be zero."""
i, j = np.mgrid[-5:6, -5:6]
image = (j >= 0).astype(float)
result = filters.scharr_h(image)
assert_allclose(result, 0)
def test_scharr_v_zeros():
"""Vertical Scharr on an array of all zeros."""
result = filters.scharr_v(np.zeros((10, 10)),
np.ones((10, 10), dtype=bool))
assert_allclose(result, 0)
def test_scharr_v_mask():
"""Vertical Scharr on a masked array should be zero."""
result = filters.scharr_v(np.random.uniform(size=(10, 10)),
np.zeros((10, 10), dtype=bool))
assert_allclose(result, 0)
def test_scharr_v_vertical():
"""Vertical Scharr on an edge should be a vertical line."""
i, j = np.mgrid[-5:6, -5:6]
image = (j >= 0).astype(float)
result = filters.scharr_v(image)
# Check if result match transform direction
assert (np.all(result[j == 0] == 1))
assert (np.all(result[np.abs(j) > 1] == 0))
def test_scharr_v_horizontal():
"""vertical Scharr on a horizontal edge should be zero."""
i, j = np.mgrid[-5:6, -5:6]
image = (i >= 0).astype(float)
result = filters.scharr_v(image)
assert_allclose(result, 0)
def test_prewitt_zeros():
"""Prewitt on an array of all zeros."""
result = filters.prewitt(np.zeros((10, 10)),
np.ones((10, 10), dtype=bool))
assert_allclose(result, 0)
def test_prewitt_mask():
"""Prewitt on a masked array should be zero."""
result = filters.prewitt(np.random.uniform(size=(10, 10)),
np.zeros((10, 10), dtype=bool))
assert_allclose(np.abs(result), 0)
def test_prewitt_horizontal():
"""Prewitt on an edge should be a horizontal line."""
i, j = np.mgrid[-5:6, -5:6]
image = (i >= 0).astype(float)
result = filters.prewitt(image) * np.sqrt(2)
# Check if result match transform direction
assert (np.all(result[i == 0] == 1))
assert_allclose(result[np.abs(i) > 1], 0, atol=1e-10)
def test_prewitt_vertical():
"""Prewitt on a vertical edge should be a vertical line."""
i, j = np.mgrid[-5:6, -5:6]
image = (j >= 0).astype(float)
result = filters.prewitt(image) * np.sqrt(2)
assert_allclose(result[j == 0], 1)
assert_allclose(result[np.abs(j) > 1], 0, atol=1e-10)
def test_prewitt_h_zeros():
"""Horizontal prewitt on an array of all zeros."""
result = filters.prewitt_h(np.zeros((10, 10)),
np.ones((10, 10), dtype=bool))
assert_allclose(result, 0)
def test_prewitt_h_mask():
"""Horizontal prewitt on a masked array should be zero."""
result = filters.prewitt_h(np.random.uniform(size=(10, 10)),
np.zeros((10, 10), dtype=bool))
assert_allclose(result, 0)
def test_prewitt_h_horizontal():
"""Horizontal prewitt on an edge should be a horizontal line."""
i, j = np.mgrid[-5:6, -5:6]
image = (i >= 0).astype(float)
result = filters.prewitt_h(image)
# Check if result match transform direction
assert (np.all(result[i == 0] == 1))
assert_allclose(result[np.abs(i) > 1], 0, atol=1e-10)
def test_prewitt_h_vertical():
"""Horizontal prewitt on a vertical edge should be zero."""
i, j = np.mgrid[-5:6, -5:6]
image = (j >= 0).astype(float)
result = filters.prewitt_h(image)
assert_allclose(result, 0, atol=1e-10)
def test_prewitt_v_zeros():
"""Vertical prewitt on an array of all zeros."""
result = filters.prewitt_v(np.zeros((10, 10)),
np.ones((10, 10), dtype=bool))
assert_allclose(result, 0)
def test_prewitt_v_mask():
"""Vertical prewitt on a masked array should be zero."""
result = filters.prewitt_v(np.random.uniform(size=(10, 10)),
np.zeros((10, 10), dtype=bool))
assert_allclose(result, 0)
def test_prewitt_v_vertical():
"""Vertical prewitt on an edge should be a vertical line."""
i, j = np.mgrid[-5:6, -5:6]
image = (j >= 0).astype(float)
result = filters.prewitt_v(image)
# Check if result match transform direction
assert (np.all(result[j == 0] == 1))
assert_allclose(result[np.abs(j) > 1], 0, atol=1e-10)
def test_prewitt_v_horizontal():
"""Vertical prewitt on a horizontal edge should be zero."""
i, j = np.mgrid[-5:6, -5:6]
image = (i >= 0).astype(float)
result = filters.prewitt_v(image)
assert_allclose(result, 0)
def test_laplace_zeros():
"""Laplace on a square image."""
# Create a synthetic 2D image
image = np.zeros((9, 9))
image[3:-3, 3:-3] = 1
result = filters.laplace(image)
check_result = np.array([[0., 0., 0., 0., 0., 0., 0., 0., 0.],
[0., 0., 0., 0., 0., 0., 0., 0., 0.],
[0., 0., 0., -1., -1., -1., 0., 0., 0.],
[0., 0., -1., 2., 1., 2., -1., 0., 0.],
[0., 0., -1., 1., 0., 1., -1., 0., 0.],
[0., 0., -1., 2., 1., 2., -1., 0., 0.],
[0., 0., 0., -1., -1., -1., 0., 0., 0.],
[0., 0., 0., 0., 0., 0., 0., 0., 0.],
[0., 0., 0., 0., 0., 0., 0., 0., 0.]])
assert_allclose(result, check_result)
def test_laplace_mask():
"""Laplace on a masked array should be zero."""
# Create a synthetic 2D image
image = np.zeros((9, 9))
image[3:-3, 3:-3] = 1
# Define the mask
result = filters.laplace(image, ksize=3, mask=np.zeros((9, 9), dtype=bool))
assert (np.all(result == 0))
def test_farid_zeros():
"""Farid on an array of all zeros."""
result = filters.farid(np.zeros((10, 10)),
mask=np.ones((10, 10), dtype=bool))
assert (np.all(result == 0))
def test_farid_mask():
"""Farid on a masked array should be zero."""
result = filters.farid(np.random.uniform(size=(10, 10)),
mask=np.zeros((10, 10), dtype=bool))
assert (np.all(result == 0))
def test_farid_horizontal():
"""Farid on a horizontal edge should be a horizontal line."""
i, j = np.mgrid[-5:6, -5:6]
image = (i >= 0).astype(float)
result = filters.farid(image) * np.sqrt(2)
# Check if result match transform direction
assert (np.all(result[i == 0] == result[i == 0][0]))
assert_allclose(result[np.abs(i) > 2], 0, atol=1e-10)
def test_farid_vertical():
"""Farid on a vertical edge should be a vertical line."""
i, j = np.mgrid[-5:6, -5:6]
image = (j >= 0).astype(float)
result = filters.farid(image) * np.sqrt(2)
assert (np.all(result[j == 0] == result[j == 0][0]))
assert_allclose(result[np.abs(j) > 2], 0, atol=1e-10)
def test_farid_h_zeros():
"""Horizontal Farid on an array of all zeros."""
result = filters.farid_h(np.zeros((10, 10)),
mask=np.ones((10, 10), dtype=bool))
assert (np.all(result == 0))
def test_farid_h_mask():
"""Horizontal Farid on a masked array should be zero."""
result = filters.farid_h(np.random.uniform(size=(10, 10)),
mask=np.zeros((10, 10), dtype=bool))
assert (np.all(result == 0))
def test_farid_h_horizontal():
"""Horizontal Farid on an edge should be a horizontal line."""
i, j = np.mgrid[-5:6, -5:6]
image = (i >= 0).astype(float)
result = filters.farid_h(image)
# Check if result match transform direction
assert np.all(result[i == 0] == result[i == 0][0])
assert_allclose(result[np.abs(i) > 2], 0, atol=1e-10)
def test_farid_h_vertical():
"""Horizontal Farid on a vertical edge should be zero."""
i, j = np.mgrid[-5:6, -5:6]
image = (j >= 0).astype(float) * np.sqrt(2)
result = filters.farid_h(image)
assert_allclose(result, 0, atol=1e-10)
def test_farid_v_zeros():
"""Vertical Farid on an array of all zeros."""
result = filters.farid_v(np.zeros((10, 10)),
mask=np.ones((10, 10), dtype=bool))
assert_allclose(result, 0, atol=1e-10)
def test_farid_v_mask():
"""Vertical Farid on a masked array should be zero."""
result = filters.farid_v(np.random.uniform(size=(10, 10)),
mask=np.zeros((10, 10), dtype=bool))
assert_allclose(result, 0)
def test_farid_v_vertical():
"""Vertical Farid on an edge should be a vertical line."""
i, j = np.mgrid[-5:6, -5:6]
image = (j >= 0).astype(float)
result = filters.farid_v(image)
# Check if result match transform direction
assert (np.all(result[j == 0] == result[j == 0][0]))
assert_allclose(result[np.abs(j) > 2], 0, atol=1e-10)
def test_farid_v_horizontal():
"""vertical Farid on a horizontal edge should be zero."""
i, j = np.mgrid[-5:6, -5:6]
image = (i >= 0).astype(float)
result = filters.farid_v(image)
assert_allclose(result, 0, atol=1e-10)
@testing.parametrize("grad_func", (filters.prewitt_h, filters.sobel_h,
filters.scharr_h))
def test_horizontal_mask_line(grad_func):
"""Horizontal edge filters mask pixels surrounding input mask."""
vgrad, _ = np.mgrid[:1:11j, :1:11j] # vertical gradient with spacing 0.1
vgrad[5, :] = 1 # bad horizontal line
mask = np.ones_like(vgrad)
mask[5, :] = 0 # mask bad line
expected = np.zeros_like(vgrad)
expected[1:-1, 1:-1] = 0.2 # constant gradient for most of image,
expected[4:7, 1:-1] = 0 # but line and neighbors masked
result = grad_func(vgrad, mask)
assert_allclose(result, expected)
@testing.parametrize("grad_func", (
filters.prewitt_v, filters.sobel_v, filters.scharr_v))
def test_vertical_mask_line(grad_func):
"""Vertical edge filters mask pixels surrounding input mask."""
_, hgrad = np.mgrid[:1:11j, :1:11j] # horizontal gradient with spacing 0.1
hgrad[:, 5] = 1 # bad vertical line
mask = np.ones_like(hgrad)
mask[:, 5] = 0 # mask bad line
expected = np.zeros_like(hgrad)
expected[1:-1, 1:-1] = 0.2 # constant gradient for most of image,
expected[1:-1, 4:7] = 0 # but line and neighbors masked
result = grad_func(hgrad, mask)
assert_allclose(result, expected)
# The below three constant 3x3x3 cubes were empirically found to maximise the
# output of each of their respective filters. We use them to test that the
# output of the filter on the blobs image matches expectation in terms of
# scale.
# maximum Sobel 3D edge on axis 0
MAX_SOBEL_0 = np.array([
[[0, 0, 0],
[0, 0, 0],
[0, 0, 0]],
[[0, 0, 0],
[0, 0, 0],
[0, 0, 0]],
[[1, 1, 1],
[1, 1, 1],
[1, 1, 1]],
]).astype(float)
# maximum Sobel 3D edge in magnitude
MAX_SOBEL_ND = np.array([
[[1, 0, 0],
[1, 0, 0],
[1, 0, 0]],
[[1, 0, 0],
[1, 1, 0],
[1, 1, 0]],
[[1, 1, 0],
[1, 1, 0],
[1, 1, 0]]
]).astype(float)
# maximum Scharr 3D edge in magnitude. This illustrates the better rotation
# invariance of the Scharr filter!
MAX_SCHARR_ND = np.array([
[[0, 0, 0],
[0, 0, 1],
[0, 1, 1]],
[[0, 0, 1],
[0, 1, 1],
[0, 1, 1]],
[[0, 0, 1],
[0, 1, 1],
[1, 1, 1]]
]).astype(float)
@testing.parametrize(
('func', 'max_edge'),
[(filters.prewitt, MAX_SOBEL_ND),
(filters.sobel, MAX_SOBEL_ND),
(filters.scharr, MAX_SCHARR_ND)]
)
def test_3d_edge_filters(func, max_edge):
blobs = data.binary_blobs(length=128, n_dim=3)
edges = func(blobs)
testing.assert_allclose(np.max(edges), func(max_edge)[1, 1, 1])
@testing.parametrize(
'func', (filters.prewitt, filters.sobel, filters.scharr)
)
def test_3d_edge_filters_single_axis(func):
blobs = data.binary_blobs(length=128, n_dim=3)
edges0 = func(blobs, axis=0)
testing.assert_allclose(np.max(edges0), func(MAX_SOBEL_0, axis=0)[1, 1, 1])
@testing.parametrize(
'detector',
[filters.sobel, filters.scharr, filters.prewitt,
filters.roberts, filters.farid]
)
def test_range(detector):
"""Output of edge detection should be in [0, 1]"""
image = np.random.random((100, 100))
out = detector(image)
assert_(
out.min() >= 0, f'Minimum of `{detector.__name__}` is smaller than 0.'
)
assert_(
out.max() <= 1, f'Maximum of `{detector.__name__}` is larger than 1.'
)