Python nifti_masker.NiftiMasker类代码示例

def test_with_files():
    # Standard masking
    data = np.zeros((40, 40, 40, 2))
    data[20, 20, 20] = 1
    data_img = Nifti1Image(data, np.eye(4))

    with testing.write_tmp_imgs(data_img) as filename:
        masker = NiftiMasker()
        masker.fit(filename)
        masker.transform(filename)

def test_detrend():
    # Check that detrending doesn't do something stupid with 3D images
    data = np.zeros((9, 9, 9))
    data[3:-3, 3:-3, 3:-3] = 10
    img = Nifti1Image(data, np.eye(4))
    mask = data.astype(np.int)
    mask_img = Nifti1Image(mask, np.eye(4))
    masker = NiftiMasker(mask_img=mask_img, detrend=True)
    # Smoke test the fit
    X = masker.fit_transform(img)
    assert_true(np.any(X != 0))

def test_resample():
    # Check that target_affine triggers the right resampling
    data = np.zeros((9, 9, 9))
    data[3:-3, 3:-3, 3:-3] = 10
    img = Nifti1Image(data, np.eye(4))
    mask = data.astype(np.int)
    mask_img = Nifti1Image(mask, np.eye(4))
    masker = NiftiMasker(mask_img=mask_img, target_affine=2 * np.eye(3))
    # Smoke test the fit
    X = masker.fit_transform(img)
    assert_true(np.any(X != 0))

def test_mask_4d():
    # Dummy mask
    mask = np.zeros((10, 10, 10), dtype=int)
    mask[3:7, 3:7, 3:7] = 1
    mask_bool = mask.astype(bool)
    mask_img = Nifti1Image(mask, np.eye(4))

    # Dummy data
    data = np.zeros((10, 10, 10, 3), dtype=int)
    data[..., 0] = 1
    data[..., 1] = 2
    data[..., 2] = 3
    data_img_4d = Nifti1Image(data, np.eye(4))
    data_imgs = [index_img(data_img_4d, 0), index_img(data_img_4d, 1),
                 index_img(data_img_4d, 2)]

    # check whether transform is indeed selecting niimgs subset
    sample_mask = np.array([0, 2])
    masker = NiftiMasker(mask_img=mask_img, sample_mask=sample_mask)
    masker.fit()
    data_trans = masker.transform(data_imgs)
    data_trans_img = index_img(data_img_4d, sample_mask)
    data_trans_direct = data_trans_img.get_data()[mask_bool, :]
    data_trans_direct = np.swapaxes(data_trans_direct, 0, 1)
    assert_array_equal(data_trans, data_trans_direct)

    masker = NiftiMasker(mask_img=mask_img, sample_mask=sample_mask)
    masker.fit()
    data_trans2 = masker.transform(data_img_4d)
    assert_array_equal(data_trans2, data_trans_direct)

def test_5d():
    mask = np.zeros((10, 10, 10))
    mask[3:7, 3:7, 3:7] = 1
    mask_img = Nifti1Image(mask, np.eye(4))

    # Test that, in list of 4d images with last dimension=1, they are
    # considered as 3d

    data_5d = [np.random.random((10, 10, 10, 3)) for i in range(5)]
    data_5d = [nibabel.Nifti1Image(d, np.eye(4)) for d in data_5d]

    masker = NiftiMasker(mask_img=mask_img)
    masker.fit()
    testing.assert_raises_regex(
        DimensionError, 'Data must be a 4D Niimg-like object but you provided'
        ' a list of 4D images.', masker.transform, data_5d)

def test_4d_single_scan():
    mask = np.zeros((10, 10, 10))
    mask[3:7, 3:7, 3:7] = 1
    mask_img = Nifti1Image(mask, np.eye(4))

    data_5d = [np.random.random((10, 10, 10, 1)) for i in range(5)]
    data_4d = [d[..., 0] for d in data_5d]
    data_5d = [nibabel.Nifti1Image(d, np.eye(4)) for d in data_5d]
    data_4d = [nibabel.Nifti1Image(d, np.eye(4)) for d in data_4d]

    masker = NiftiMasker(mask_img=mask_img)
    masker.fit()
    data_trans_5d = masker.transform(data_5d)
    data_trans_4d = masker.transform(data_4d)

    assert_array_equal(data_trans_4d, data_trans_5d)

def test_5d():
    mask = np.zeros((10, 10, 10))
    mask[3:7, 3:7, 3:7] = 1
    mask_img = Nifti1Image(mask, np.eye(4))

    # Test that, in list of 4d images with last dimension=1, they are
    # considered as 3d

    data_5d = [np.random.random((10, 10, 10, 3)) for i in range(5)]
    data_5d = [nibabel.Nifti1Image(d, np.eye(4)) for d in data_5d]

    masker = NiftiMasker(mask_img=mask_img)
    masker.fit()
    testing.assert_raises_regex(
        DimensionError,
        "Input data has incompatible dimensionality: "
        "Expected dimension is 4D and you provided "
        "a list of 4D images \(5D\).",
        masker.transform, data_5d)

def test_dtype():
    data_32 = np.zeros((9, 9, 9), dtype=np.float32)
    data_64 = np.zeros((9, 9, 9), dtype=np.float64)
    data_32[2:-2, 2:-2, 2:-2] = 10
    data_64[2:-2, 2:-2, 2:-2] = 10

    affine_32 = np.eye(4, dtype=np.float32)
    affine_64 = np.eye(4, dtype=np.float64)

    img_32 = Nifti1Image(data_32, affine_32)
    img_64 = Nifti1Image(data_64, affine_64)

    masker_1 = NiftiMasker(dtype='auto')
    assert(masker_1.fit_transform(img_32).dtype == np.float32)
    assert(masker_1.fit_transform(img_64).dtype == np.float32)

    masker_2 = NiftiMasker(dtype='float64')
    assert(masker_2.fit_transform(img_32).dtype == np.float64)
    assert(masker_2.fit_transform(img_64).dtype == np.float64)

def test_nan():
    data = np.ones((9, 9, 9))
    data[0] = np.nan
    data[:, 0] = np.nan
    data[:, :, 0] = np.nan
    data[-1] = np.nan
    data[:, -1] = np.nan
    data[:, :, -1] = np.nan
    data[3:-3, 3:-3, 3:-3] = 10
    img = Nifti1Image(data, np.eye(4))
    masker = NiftiMasker(mask_args=dict(opening=0))
    masker.fit(img)
    mask = masker.mask_img_.get_data()
    assert_true(mask[1:-1, 1:-1, 1:-1].all())
    assert_false(mask[0].any())
    assert_false(mask[:, 0].any())
    assert_false(mask[:, :, 0].any())
    assert_false(mask[-1].any())
    assert_false(mask[:, -1].any())
    assert_false(mask[:, :, -1].any())

def test_joblib_cache():
    if not LooseVersion(nibabel.__version__) > LooseVersion('1.1.0'):
        # Old nibabel do not pickle
        raise SkipTest
    from sklearn.externals.joblib import hash, Memory
    mask = np.zeros((40, 40, 40))
    mask[20, 20, 20] = 1
    mask_img = Nifti1Image(mask, np.eye(4))

    with testing.write_tmp_imgs(mask_img, create_files=True)\
            as filename:
        masker = NiftiMasker(mask_img=filename)
        masker.fit()
        mask_hash = hash(masker.mask_img_)
        masker.mask_img_.get_data()
        assert_true(mask_hash == hash(masker.mask_img_))

    # Test a tricky issue with memmapped joblib.memory that makes
    # imgs return by inverse_transform impossible to save
    cachedir = mkdtemp()
    try:
        masker.memory = Memory(cachedir=cachedir, mmap_mode='r',
                               verbose=0)
        X = masker.transform(mask_img)
        # inverse_transform a first time, so that the result is cached
        out_img = masker.inverse_transform(X)
        out_img = masker.inverse_transform(X)
        out_img.to_filename(os.path.join(cachedir, 'test.nii'))
    finally:
        shutil.rmtree(cachedir, ignore_errors=True)

def test_auto_mask():
    # This mostly a smoke test
    data = np.zeros((9, 9, 9))
    data[3:-3, 3:-3, 3:-3] = 10
    img = Nifti1Image(data, np.eye(4))
    masker = NiftiMasker()
    # Smoke test the fit
    masker.fit(img)
    # Smoke test the transform
    # With a 4D img
    masker.transform([img, ])
    # With a 3D img
    masker.transform(img)

    # check exception when transform() called without prior fit()
    masker2 = NiftiMasker(mask_img=img)
    testing.assert_raises_regex(
        ValueError,
        'has not been fitted. ', masker2.transform, img)

def test_matrix_orientation():
    """Test if processing is performed along the correct axis."""

    # the "step" kind generate heavyside-like signals for each voxel.
    # all signals being identical, standardizing along the wrong axis
    # would leave a null signal. Along the correct axis, the step remains.
    fmri, mask = testing.generate_fake_fmri(shape=(40, 41, 42), kind="step")
    masker = NiftiMasker(mask_img=mask, standardize=True, detrend=True)
    timeseries = masker.fit_transform(fmri)
    assert(timeseries.shape[0] == fmri.shape[3])
    assert(timeseries.shape[1] == mask.get_data().sum())
    std = timeseries.std(axis=0)
    assert(std.shape[0] == timeseries.shape[1])  # paranoid
    assert(not np.any(std < 0.1))

    # Test inverse transform
    masker = NiftiMasker(mask_img=mask, standardize=False, detrend=False)
    masker.fit()
    timeseries = masker.transform(fmri)
    recovered = masker.inverse_transform(timeseries)
    np.testing.assert_array_almost_equal(recovered.get_data(), fmri.get_data())

def test_compute_gray_matter_mask():
    # Check masker for template masking strategy

    img = np.random.rand(9, 9, 5)
    img = Nifti1Image(img, np.eye(4))

    masker = NiftiMasker(mask_strategy='template')

    masker.fit(img)
    mask1 = masker.mask_img_

    masker2 = NiftiMasker(mask_strategy='template',
                          mask_args=dict(threshold=0.))

    masker2.fit(img)
    mask2 = masker2.mask_img_

    mask_ref = np.zeros((9, 9, 5))
    mask_ref[2:7, 2:7, 2] = 1

    np.testing.assert_array_equal(mask1.get_data(), mask_ref)
    np.testing.assert_array_equal(mask2.get_data(), mask_ref)

def test_compute_epi_mask():
    # Taken from test_masking.py, but used to test that the masker class
    #   is passing parameters appropriately.
    mean_image = np.ones((9, 9, 3))
    mean_image[3:-2, 3:-2, :] = 10
    mean_image[5, 5, :] = 11
    mean_image = Nifti1Image(mean_image.astype(float), np.eye(4))

    masker = NiftiMasker(mask_strategy='epi',
                         mask_args=dict(opening=False))
    masker.fit(mean_image)
    mask1 = masker.mask_img_

    masker2 = NiftiMasker(mask_strategy='epi',
                          mask_args=dict(opening=False, exclude_zeros=True))
    masker2.fit(mean_image)
    mask2 = masker2.mask_img_

    # With an array with no zeros, exclude_zeros should not make
    # any difference
    np.testing.assert_array_equal(mask1.get_data(), mask2.get_data())

    # Check that padding with zeros does not change the extracted mask
    mean_image2 = np.zeros((30, 30, 3))
    mean_image2[3:12, 3:12, :] = mean_image.get_data()
    mean_image2 = Nifti1Image(mean_image2, np.eye(4))

    masker3 = NiftiMasker(mask_strategy='epi',
                          mask_args=dict(opening=False, exclude_zeros=True))
    masker3.fit(mean_image2)
    mask3 = masker3.mask_img_
    np.testing.assert_array_equal(mask1.get_data(),
                                  mask3.get_data()[3:12, 3:12])

    # However, without exclude_zeros, it does
    masker4 = NiftiMasker(mask_strategy='epi', mask_args=dict(opening=False))
    masker4.fit(mean_image2)
    mask4 = masker4.mask_img_

    assert_false(np.allclose(mask1.get_data(),
                             mask4.get_data()[3:12, 3:12]))