def test_region_extractor_fit_and_transform():
n_regions = 9
n_subjects = 5
maps, mask_img = generate_maps((40, 40, 40), n_regions=n_regions)
# smoke test to RegionExtractor with thresholding_strategy='ratio_n_voxels'
extract_ratio = RegionExtractor(maps, threshold=0.2,
thresholding_strategy='ratio_n_voxels')
extract_ratio.fit()
assert_not_equal(extract_ratio.regions_img_, '')
assert_true(extract_ratio.regions_img_.shape[-1] >= 9)
# smoke test with threshold=string and strategy=percentile
extractor = RegionExtractor(maps, threshold=30,
thresholding_strategy='percentile',
mask_img=mask_img)
extractor.fit()
assert_true(extractor.index_, np.ndarray)
assert_not_equal(extractor.regions_img_, '')
assert_true(extractor.regions_img_.shape[-1] >= 9)
n_regions_extracted = extractor.regions_img_.shape[-1]
shape = (91, 109, 91, 7)
expected_signal_shape = (7, n_regions_extracted)
for id_ in range(n_subjects):
img, data = _make_random_data(shape)
# smoke test NiftiMapsMasker transform inherited in Region Extractor
signal = extractor.transform(img)
assert_equal(expected_signal_shape, signal.shape)
def test_region_extractor_fit_and_transform():
n_regions = 9
n_subjects = 5
maps, mask_img = generate_maps((40, 40, 40), n_regions=n_regions)
# smoke test to RegionExtractor with thresholding_strategy='ratio_n_voxels'
extract_ratio = RegionExtractor(maps,
threshold=0.2,
thresholding_strategy='ratio_n_voxels')
extract_ratio.fit()
assert_not_equal(extract_ratio.regions_img_, '')
assert_true(extract_ratio.regions_img_.shape[-1] >= 9)
# smoke test with threshold=string and strategy=percentile
extractor = RegionExtractor(maps,
threshold=30,
thresholding_strategy='percentile',
mask_img=mask_img)
extractor.fit()
assert_true(extractor.index_, np.ndarray)
assert_not_equal(extractor.regions_img_, '')
assert_true(extractor.regions_img_.shape[-1] >= 9)
n_regions_extracted = extractor.regions_img_.shape[-1]
shape = (91, 109, 91, 7)
expected_signal_shape = (7, n_regions_extracted)
for id_ in range(n_subjects):
img, data = _make_random_data(shape)
# smoke test NiftiMapsMasker transform inherited in Region Extractor
signal = extractor.transform(img)
assert_equal(expected_signal_shape, signal.shape)
# smoke test with high resolution image
maps, mask_img = generate_maps((20, 20, 20),
n_regions=n_regions,
affine=.2 * np.eye(4))
extract_ratio = RegionExtractor(maps,
thresholding_strategy='ratio_n_voxels',
smoothing_fwhm=.6,
min_region_size=.4)
extract_ratio.fit()
assert_not_equal(extract_ratio.regions_img_, '')
assert_true(extract_ratio.regions_img_.shape[-1] >= 9)
# smoke test with zeros on the diagonal of the affine
affine = np.eye(4)
affine[[0, 1]] = affine[[1, 0]] # permutes first and second lines
maps, mask_img = generate_maps((40, 40, 40),
n_regions=n_regions,
affine=affine)
extract_ratio = RegionExtractor(maps,
threshold=0.2,
thresholding_strategy='ratio_n_voxels')
extract_ratio.fit()
assert_not_equal(extract_ratio.regions_img_, '')
assert_true(extract_ratio.regions_img_.shape[-1] >= 9)
def test_threshold_as_none_and_string_cases():
maps, _ = generate_maps((6, 8, 10), n_regions=1)
extract_thr_none_check = RegionExtractor(maps, threshold=None)
with pytest.raises(ValueError,
match="The given input to threshold is not valid."):
extract_thr_none_check.fit()
extract_thr_string_check = RegionExtractor(maps, threshold='30%')
with pytest.raises(ValueError,
match="The given input to threshold is not valid."):
extract_thr_string_check.fit()
def test_threshold_as_none_and_string_cases():
maps, _ = generate_maps((6, 8, 10), n_regions=1)
extract_thr_none_check = RegionExtractor(maps, threshold=None)
assert_raises_regex(ValueError,
"The given input to threshold is not valid.",
extract_thr_none_check.fit)
extract_thr_string_check = RegionExtractor(maps, threshold='30%')
assert_raises_regex(ValueError,
"The given input to threshold is not valid.",
extract_thr_string_check.fit)
def test_invalid_threshold_strategies():
maps, _ = generate_maps((6, 8, 10), n_regions=1)
extract_strategy_check = RegionExtractor(maps, thresholding_strategy='n_')
valid_strategies = ['ratio_n_voxels', 'img_value', 'percentile']
assert_raises_regex(
ValueError, "'thresholding_strategy' should be either of "
"these".format(valid_strategies), extract_strategy_check.fit)
plotting.plot_prob_atlas(components_img,
view_type='filled_contours',
title='Dictionary Learning maps')
################################################################################
# Extracting regions from networks
# Import Region Extractor algorithm from regions module
# threshold=0.5 indicates that we keep nominal of amount nonzero voxels across all
# maps, less the threshold means that more intense non-voxels will be survived.
from nilearn.regions import RegionExtractor
extractor = RegionExtractor(components_img,
threshold=0.5,
thresholding_strategy='ratio_n_voxels',
extractor='local_regions',
standardize=True,
min_region_size=1350)
# Just call fit() to process for regions extraction
extractor.fit()
# Extracted regions are stored in regions_img_
regions_extracted_img = extractor.regions_img_
# Each region index is stored in index_
regions_index = extractor.index_
# Total number of regions extracted
n_regions_extracted = regions_extracted_img.shape[-1]
# Visualization of region extraction results
title = ('%d regions are extracted from %d components.'
'\nEach separate color of region indicates extracted region' %
(n_regions_extracted, 5))
#################################################################################
####################### REGION EXTRACTOR ######################################
################################################################################
# Extract regions from networks
# ------------------------------
# Import Region Extractor algorithm from regions module
# threshold=0.5 indicates that we keep nominal of amount nonzero voxels across all
# maps, less the threshold means that more intense non-voxels will be survived.
from nilearn.regions import RegionExtractor
extractor = RegionExtractor(atlas_harvard_oxford.maps,
threshold=2,
thresholding_strategy='ratio_n_voxels',
extractor='local_regions',
standardize=True,
min_region_size=512)
# Just call fit() to process for regions extraction
extractor.fit()
# Extracted regions are stored in regions_img_
regions_extracted_img = extractor.regions_img_
# Each region index is stored in index_
regions_index = extractor.index_
# Total number of regions extracted
n_regions_extracted = regions_extracted_img.shape[-1]
# Visualization of region extraction results
title = ('%d regions are extracted from %d components.'
'\nEach separate color of region indicates extracted region' %
(n_regions_extracted, 3))
"""
################################################################################
# Fetching the smith ICA 10 RSN by importing datasets utilities
from nilearn import datasets
smith_atlas = datasets.fetch_atlas_smith_2009()
atlas_networks = smith_atlas.rsn10
################################################################################
# Import region extractor to extract atlas networks
from nilearn.regions import RegionExtractor
# min_region_size in voxel volume mm^3
extraction = RegionExtractor(atlas_networks,
min_region_size=800,
threshold=98,
thresholding_strategy='percentile')
# Just call fit() to execute region extraction procedure
extraction.fit()
regions_img = extraction.regions_img_
################################################################################
# Visualization
# Show region extraction results by importing image & plotting utilities
from nilearn import plotting
from nilearn.image import index_img
from nilearn.plotting import find_xyz_cut_coords
# Showing region extraction results using 4D maps visualization tool
plotting.plot_prob_atlas(regions_img,
