def test_smooth_pinv():
hemi = hemi_icosahedron.subdivide(2)
m, n = sph_harm_ind_list(4)
with warnings.catch_warnings():
warnings.filterwarnings("ignore",
message=descoteaux07_legacy_msg,
category=PendingDeprecationWarning)
B = real_sh_descoteaux_from_index(m, n, hemi.theta[:, None],
hemi.phi[:, None])
L = np.zeros(len(m))
C = smooth_pinv(B, L)
D = np.dot(npl.inv(np.dot(B.T, B)), B.T)
assert_array_almost_equal(C, D)
L = n * (n + 1) * .05
C = smooth_pinv(B, L)
L = np.diag(L)
D = np.dot(npl.inv(np.dot(B.T, B) + L * L), B.T)
assert_array_almost_equal(C, D)
L = np.arange(len(n)) * .05
C = smooth_pinv(B, L)
L = np.diag(L)
D = np.dot(npl.inv(np.dot(B.T, B) + L * L), B.T)
assert_array_almost_equal(C, D)
def test_sh_to_sf_matrix():
sphere = Sphere(xyz=hemi_icosahedron.vertices)
with warnings.catch_warnings():
warnings.filterwarnings("ignore",
message=descoteaux07_legacy_msg,
category=PendingDeprecationWarning)
B1, invB1 = sh_to_sf_matrix(sphere)
B2, m, n = real_sh_descoteaux(4, sphere.theta, sphere.phi)
invB2 = smooth_pinv(B2, L=np.zeros_like(n))
with warnings.catch_warnings():
warnings.filterwarnings("ignore",
message=descoteaux07_legacy_msg,
category=PendingDeprecationWarning)
B3 = sh_to_sf_matrix(sphere, return_inv=False)
assert_array_almost_equal(B1, B2.T)
assert_array_almost_equal(invB1, invB2.T)
assert_array_almost_equal(B3, B1)
assert_raises(ValueError, sh_to_sf_matrix, sphere, basis_type="")
def test_real_sh_descoteaux2():
vertices = hemi_icosahedron.subdivide(2).vertices
mevals = np.array([[0.0015, 0.0003, 0.0003], [0.0015, 0.0003, 0.0003]])
angles = [(0, 0), (60, 0)]
odf = multi_tensor_odf(vertices, mevals, angles, [50, 50])
mevals = np.array([[0.0015, 0.0003, 0.0003]])
angles = [(0, 0)]
odf2 = multi_tensor_odf(-vertices, mevals, angles, [100])
sphere = Sphere(xyz=np.vstack((vertices, -vertices)))
# Asymmetric spherical function with 162 coefficients
sf = np.append(odf, odf2)
# In order for our approximation to be precise enough, we
# will use a SH basis of orders up to 10 (121 coefficients)
with warnings.catch_warnings(record=True) as w:
B, m, n = real_sh_descoteaux(10,
sphere.theta,
sphere.phi,
full_basis=True)
npt.assert_equal(len(w), 1)
npt.assert_(issubclass(w[0].category, PendingDeprecationWarning))
npt.assert_(descoteaux07_legacy_msg in str(w[0].message))
invB = smooth_pinv(B, L=np.zeros_like(n))
sh_coefs = np.dot(invB, sf)
sf_approx = np.dot(B, sh_coefs)
assert_array_almost_equal(sf_approx, sf, 2)
def main():
parser = _build_arg_parser()
args = parser.parse_args()
assert_inputs_exist(parser, args.input_sh)
assert_outputs_exist(parser, args, args.output_name)
input_basis = args.sh_basis
output_basis = 'descoteaux07' if input_basis == 'tournier07' else 'tournier07'
sph_harm_basis_ori = sph_harm_lookup.get(input_basis)
sph_harm_basis_des = sph_harm_lookup.get(output_basis)
sphere = get_sphere('repulsion724').subdivide(1)
img = nib.load(args.input_sh)
data = img.get_data()
sh_order = find_order_from_nb_coeff(data)
b_ori, m_ori, n_ori = sph_harm_basis_ori(sh_order, sphere.theta,
sphere.phi)
b_des, m_des, n_des = sph_harm_basis_des(sh_order, sphere.theta,
sphere.phi)
l_des = -n_des * (n_des + 1)
inv_b_des = smooth_pinv(b_des, 0 * l_des)
indices = np.argwhere(np.any(data, axis=3))
for i, ind in enumerate(indices):
ind = tuple(ind)
sf_1 = np.dot(data[ind], b_ori.T)
data[ind] = np.dot(sf_1, inv_b_des.T)
img = nib.Nifti1Image(data, img.affine, img.header)
nib.save(nib.Nifti1Image(data, img.affine, img.header), args.output_name)
def sh_smooth(data, bvals, bvecs, sh_order=4, similarity_threshold=50, regul=0.006):
"""Smooth the raw diffusion signal with spherical harmonics.
data : ndarray
The diffusion data to smooth.
gtab : gradient table object
Corresponding gradients table object to data.
sh_order : int, default 8
Order of the spherical harmonics to fit.
similarity_threshold : int, default 50
All b-values such that |b_1 - b_2| < similarity_threshold
will be considered as identical for smoothing purpose.
Must be lower than 200.
regul : float, default 0.006
Amount of regularization to apply to sh coefficients computation.
Return
---------
pred_sig : ndarray
The smoothed diffusion data, fitted through spherical harmonics.
"""
if similarity_threshold > 200:
raise ValueError("similarity_threshold = {}, which is higher than 200,"
" please use a lower value".format(similarity_threshold))
m, n = sph_harm_ind_list(sh_order)
L = -n * (n + 1)
where_b0s = bvals == 0
pred_sig = np.zeros_like(data, dtype=np.float32)
# Round similar bvals together for identifying similar shells
rounded_bvals = np.zeros_like(bvals)
for unique_bval in np.unique(bvals):
idx = np.abs(unique_bval - bvals) < similarity_threshold
rounded_bvals[idx] = unique_bval
# process each b-value separately
for unique_bval in np.unique(rounded_bvals):
idx = rounded_bvals == unique_bval
# Just give back the signal for the b0s since we can't really do anything about it
if np.all(idx == where_b0s):
if np.sum(where_b0s) > 1:
pred_sig[..., idx] = np.mean(data[..., idx], axis=-1, keepdims=True)
else:
pred_sig[..., idx] = data[..., idx]
continue
x, y, z = bvecs[:, idx]
r, theta, phi = cart2sphere(x, y, z)
# Find the sh coefficients to smooth the signal
B_dwi = real_sph_harm(m, n, theta[:, None], phi[:, None])
invB = smooth_pinv(B_dwi, np.sqrt(regul) * L)
sh_coeff = np.dot(data[..., idx], invB.T)
# Find the smoothed signal from the sh fit for the given gtab
pred_sig[..., idx] = np.dot(sh_coeff, B_dwi.T)
return pred_sig
def sf_to_sh_invB(sphere, sh_order=8, basis_type=None, smooth=0.0):
sph_harm_basis = sph_harm_lookup.get(basis_type)
if sph_harm_basis is None:
raise ValueError("Invalid basis name.")
B, m, n = sph_harm_basis(sh_order, sphere.theta, sphere.phi)
L = -n * (n + 1)
invB = smooth_pinv(B, np.sqrt(smooth) * L)
return invB.T
def process(self, data_container, points, dwi):
raw_sphere = Sphere(xyz=data_container.bvecs)
real_sh, _, n = real_sym_sh_mrtrix(self.sh_order, raw_sphere.theta,
raw_sphere.phi)
l = -n * (n + 1)
inv_b = smooth_pinv(real_sh, np.sqrt(self.smooth) * l)
data_sh = np.dot(dwi, inv_b.T)
return data_sh
def get_spherical_harmonics_coefficients(dwi, bvals, bvecs, sh_order=8, smooth=0.006, first=False, mean_centering=True):
""" Compute coefficients of the spherical harmonics basis.
Parameters
-----------
dwi : `nibabel.NiftiImage` object
Diffusion signal as weighted images (4D).
bvals : ndarray shape (N,)
B-values used with each direction.
bvecs : ndarray shape (N, 3)
Directions of the diffusion signal. Directions are
assumed to be only on the hemisphere.
sh_order : int, optional
SH order. Default: 8
smooth : float, optional
Lambda-regularization in the SH fit. Default: 0.006.
mean_centering : bool
If True, signal will have zero mean in each direction for all nonzero voxels
Returns
-------
sh_coeffs : ndarray of shape (X, Y, Z, #coeffs)
Spherical harmonics coefficients at every voxel. The actual number of
coeffs depends on `sh_order`.
"""
bvals = np.asarray(bvals)
bvecs = np.asarray(bvecs)
dwi_weights = dwi.get_data().astype("float32")
# Exract the averaged b0.
b0_idx = bvals == 0
b0 = dwi_weights[..., b0_idx].mean(axis=3)
# Extract diffusion weights and normalize by the b0.
bvecs = bvecs[np.logical_not(b0_idx)]
weights = dwi_weights[..., np.logical_not(b0_idx)]
weights = normalize_dwi(weights, b0)
# Assuming all directions are on the hemisphere.
raw_sphere = HemiSphere(xyz=bvecs)
# Fit SH to signal
sph_harm_basis = sph_harm_lookup.get('mrtrix')
Ba, m, n = sph_harm_basis(sh_order, raw_sphere.theta, raw_sphere.phi)
L = -n * (n + 1)
invB = smooth_pinv(Ba, np.sqrt(smooth) * L)
data_sh = np.dot(weights, invB.T)
if mean_centering:
# Normalization in each direction (zero mean)
idx = data_sh.sum(axis=-1).nonzero()
means = data_sh[idx].mean(axis=0)
data_sh[idx] -= means
return data_sh
def __init__(self, odf_data, basis, sphere):
self.basis = basis
self.order = find_order_from_nb_coeff(odf_data)
self.sphere = sphere
B, self.m, self.n = get_b_matrix(self.order,
self.sphere,
self.basis,
return_all=True)
self.B = np.ascontiguousarray(np.matrix(B), dtype=np.float64)
invB = smooth_pinv(self.B, np.sqrt(0.006) * (-self.n * (self.n + 1)))
self.invB = np.ascontiguousarray(np.matrix(invB), dtype=np.float64)
def test_sh_to_sf_matrix():
sphere = Sphere(xyz=hemi_icosahedron.vertices)
B1, invB1 = sh_to_sf_matrix(sphere)
B2, m, n = real_sym_sh_basis(4, sphere.theta, sphere.phi)
invB2 = smooth_pinv(B2, L=np.zeros_like(n))
B3 = sh_to_sf_matrix(sphere, return_inv=False)
assert_array_almost_equal(B1, B2.T)
assert_array_almost_equal(invB1, invB2.T)
assert_array_almost_equal(B3, B1)
assert_raises(ValueError, sh_to_sf_matrix, sphere, basis_type="")
def test_smooth_pinv():
hemi = hemi_icosahedron.subdivide(2)
m, n = sph_harm_ind_list(4)
B = real_sph_harm(m, n, hemi.theta[:, None], hemi.phi[:, None])
L = np.zeros(len(m))
C = smooth_pinv(B, L)
D = np.dot(npl.inv(np.dot(B.T, B)), B.T)
assert_array_almost_equal(C, D)
L = n * (n + 1) * .05
C = smooth_pinv(B, L)
L = np.diag(L)
D = np.dot(npl.inv(np.dot(B.T, B) + L * L), B.T)
assert_array_almost_equal(C, D)
L = np.arange(len(n)) * .05
C = smooth_pinv(B, L)
L = np.diag(L)
D = np.dot(npl.inv(np.dot(B.T, B) + L * L), B.T)
assert_array_almost_equal(C, D)
def test_smooth_pinv():
hemi = hemi_icosahedron.subdivide(2)
m, n = sph_harm_ind_list(4)
B = real_sph_harm(m, n, hemi.theta[:, None], hemi.phi[:, None])
L = np.zeros(len(m))
C = smooth_pinv(B, L)
D = np.dot(npl.inv(np.dot(B.T, B)), B.T)
assert_array_almost_equal(C, D)
L = n * (n + 1) * .05
C = smooth_pinv(B, L)
L = np.diag(L)
D = np.dot(npl.inv(np.dot(B.T, B) + L * L), B.T)
assert_array_almost_equal(C, D)
L = np.arange(len(n)) * .05
C = smooth_pinv(B, L)
L = np.diag(L)
D = np.dot(npl.inv(np.dot(B.T, B) + L * L), B.T)
assert_array_almost_equal(C, D)
def test_smooth_pinv():
v, e, f = create_half_unit_sphere(3)
m, n = sph_harm_ind_list(4)
r, pol, azi = cart2sphere(*v.T)
B = real_sph_harm(m, n, azi[:, None], pol[:, None])
L = np.zeros(len(m))
C = smooth_pinv(B, L)
D = np.dot(npl.inv(np.dot(B.T, B)), B.T)
assert_array_almost_equal(C, D)
L = n * (n + 1) * 0.05
C = smooth_pinv(B, L)
L = np.diag(L)
D = np.dot(npl.inv(np.dot(B.T, B) + L * L), B.T)
assert_array_almost_equal(C, D)
L = np.arange(len(n)) * 0.05
C = smooth_pinv(B, L)
L = np.diag(L)
D = np.dot(npl.inv(np.dot(B.T, B) + L * L), B.T)
assert_array_almost_equal(C, D)
def test_smooth_pinv():
v, e, f = create_half_unit_sphere(3)
m, n = sph_harm_ind_list(4)
r, pol, azi = cart2sphere(*v.T)
B = real_sph_harm(m, n, azi[:, None], pol[:, None])
L = np.zeros(len(m))
C = smooth_pinv(B, L)
D = np.dot(npl.inv(np.dot(B.T, B)), B.T)
assert_array_almost_equal(C, D)
L = n * (n + 1) * .05
C = smooth_pinv(B, L)
L = np.diag(L)
D = np.dot(npl.inv(np.dot(B.T, B) + L * L), B.T)
assert_array_almost_equal(C, D)
L = np.arange(len(n)) * .05
C = smooth_pinv(B, L)
L = np.diag(L)
D = np.dot(npl.inv(np.dot(B.T, B) + L * L), B.T)
assert_array_almost_equal(C, D)
def get_spherical_harmonics_coefficients(dwi, bvals, bvecs, sh_order=8, smooth=0.006, first=False):
""" Compute coefficients of the spherical harmonics basis.
Parameters
-----------
dwi : `nibabel.NiftiImage` object
Diffusion signal as weighted images (4D).
bvals : ndarray shape (N,)
B-values used with each direction.
bvecs : ndarray shape (N, 3)
Directions of the diffusion signal. Directions are
assumed to be only on the hemisphere.
sh_order : int, optional
SH order. Default: 8
smooth : float, optional
Lambda-regularization in the SH fit. Default: 0.006.
Returns
-------
sh_coeffs : ndarray of shape (X, Y, Z, #coeffs)
Spherical harmonics coefficients at every voxel. The actual number of
coeffs depends on `sh_order`.
"""
bvals = np.asarray(bvals)
bvecs = np.asarray(bvecs)
dwi_weights = dwi.get_data().astype("float32")
# Exract the averaged b0.
b0_idx = bvals == 0
b0 = dwi_weights[..., b0_idx].mean(axis=3)
# Extract diffusion weights and normalize by the b0.
bvecs = bvecs[np.logical_not(b0_idx)]
weights = dwi_weights[..., np.logical_not(b0_idx)]
weights = normalize_dwi(weights, b0)
# Assuming all directions are on the hemisphere.
raw_sphere = HemiSphere(xyz=bvecs)
# Fit SH to signal
sph_harm_basis = sph_harm_lookup.get('mrtrix')
Ba, m, n = sph_harm_basis(sh_order, raw_sphere.theta, raw_sphere.phi)
L = -n * (n + 1)
invB = smooth_pinv(Ba, np.sqrt(smooth) * L)
data_sh = np.dot(weights, invB.T)
return data_sh
def get_spherical_harmonics_coefficients(self,
dwi_weights,
bvals,
bvecs,
sh_order=8,
smooth=0.006):
""" Compute coefficients of the spherical harmonics basis.
Parameters
-----------
dwi_weights : `nibabel.NiftiImage` object
Diffusion signal as weighted images (4D).
bvals : ndarray shape (N,)
B-values used with each direction.
bvecs : ndarray shape (N, 3)
Directions of the diffusion signal. Directions are
assumed to be only on the hemisphere.
sh_order : int, optional
SH order. Default: 8
smooth : float, optional
Lambda-regularization in the SH fit. Default: 0.006.
Returns
-------
sh_coeffs : ndarray of shape (X, Y, Z, #coeffs)
Spherical harmonics coefficients at every voxel. The actual number of
coeffs depends on `sh_order`.
"""
# Exract the averaged b0.
b0_idx = bvals == 0
b0 = dwi_weights[..., b0_idx].mean(axis=3) + 1e-10
# Extract diffusion weights and normalize by the b0.
bvecs = bvecs[np.logical_not(b0_idx)]
weights = dwi_weights[..., np.logical_not(b0_idx)]
weights = self.normalize_dwi(weights, b0)
# Assuming all directions are on the hemisphere.
raw_sphere = HemiSphere(xyz=bvecs)
# Fit SH to signal
sph_harm_basis = sph_harm_lookup.get("tournier07")
Ba, m, n = sph_harm_basis(sh_order, raw_sphere.theta, raw_sphere.phi)
L = -n * (n + 1)
invB = smooth_pinv(Ba, np.sqrt(smooth) * L)
data_sh = np.dot(weights, invB.T)
return data_sh
def test_real_full_sh_basis():
vertices = hemi_icosahedron.subdivide(2).vertices
mevals = np.array([[0.0015, 0.0003, 0.0003], [0.0015, 0.0003, 0.0003]])
angles = [(0, 0), (60, 0)]
odf = multi_tensor_odf(vertices, mevals, angles, [50, 50])
mevals = np.array([[0.0015, 0.0003, 0.0003]])
angles = [(0, 0)]
odf2 = multi_tensor_odf(-vertices, mevals, angles, [100])
sphere = Sphere(xyz=np.vstack((vertices, -vertices)))
# Asymmetric spherical function with 162 coefficients
sf = np.append(odf, odf2)
# In order for our approximation to be precise enough, we
# will use a SH basis of orders up to 10 (121 coefficients)
B, m, n = real_full_sh_basis(10, sphere.theta, sphere.phi)
invB = smooth_pinv(B, L=np.zeros_like(n))
sh_coefs = np.dot(invB, sf)
sf_approx = np.dot(B, sh_coefs)
assert_array_almost_equal(sf_approx, sf, 2)
def get_B_matrix(gtab=None, sh_order=8, theta=None, phi=None, smooth=0.006):
"""Function that return matrices for Spherical Harmonics fitting
Attributes:
gtab (dipy GradientTable): the gradient of the dwi to be fitted
sh_order (int): Order of the Spherical Harmonics
theta: custom gradient angle used instead of gtab in combinaison w/ phi
phi: same as theta
smooth (float): the smoothing parameter for the laplacian
Returns:
B (np.array(nb_dwi_directions, nb_sh_coeff)): matrix to fit SH->DWI
invB (np.array(nb_sh_coeff, nb_dwi_directions)): matrix to fit DWI->SH
"""
if theta is None or phi is None:
x, y, z = gtab.gradients[~gtab.b0s_mask].T
r, theta, phi = cart2sphere(x, y, z)
B, m, n = real_sym_sh_basis(sh_order, theta[:, None], phi[:, None])
# B = real_sph_harm(m, n, theta[:, None], phi[:, None])
L = -n * (n + 1)
invB = smooth_pinv(B, np.sqrt(smooth) * L)
return B, invB
def sh_smooth(data,
bvals,
bvecs,
sh_order=4,
similarity_threshold=50,
regul=0.006):
"""Smooth the raw diffusion signal with spherical harmonics.
data : ndarray
The diffusion data to smooth.
gtab : gradient table object
Corresponding gradients table object to data.
sh_order : int, default 8
Order of the spherical harmonics to fit.
similarity_threshold : int, default 50
All b-values such that |b_1 - b_2| < similarity_threshold
will be considered as identical for smoothing purpose.
Must be lower than 200.
regul : float, default 0.006
Amount of regularization to apply to sh coefficients computation.
Return
---------
pred_sig : ndarray
The smoothed diffusion data, fitted through spherical harmonics.
"""
if similarity_threshold > 200:
raise ValueError(
"similarity_threshold = {}, which is higher than 200,"
" please use a lower value".format(similarity_threshold))
m, n = sph_harm_ind_list(sh_order)
L = -n * (n + 1)
where_b0s = bvals == 0
pred_sig = np.zeros_like(data, dtype=np.float32)
# Round similar bvals together for identifying similar shells
rounded_bvals = np.zeros_like(bvals)
for unique_bval in np.unique(bvals):
idx = np.abs(unique_bval - bvals) < similarity_threshold
rounded_bvals[idx] = unique_bval
# process each b-value separately
for unique_bval in np.unique(rounded_bvals):
idx = rounded_bvals == unique_bval
# Just give back the signal for the b0s since we can't really do anything about it
if np.all(idx == where_b0s):
if np.sum(where_b0s) > 1:
pred_sig[..., idx] = np.mean(data[..., idx],
axis=-1,
keepdims=True)
else:
pred_sig[..., idx] = data[..., idx]
continue
x, y, z = bvecs[:, idx]
r, theta, phi = cart2sphere(x, y, z)
# Find the sh coefficients to smooth the signal
B_dwi = real_sph_harm(m, n, theta[:, None], phi[:, None])
invB = smooth_pinv(B_dwi, np.sqrt(regul) * L)
sh_coeff = np.dot(data[..., idx], invB.T)
# Find the smoothed signal from the sh fit for the given gtab
pred_sig[..., idx] = np.dot(sh_coeff, B_dwi.T)
return pred_sig
def peaks_from_model(model, data, sphere, relative_peak_threshold,
min_separation_angle, mask=None, return_odf=False,
return_sh=True, gfa_thr=0, normalize_peaks=False,
sh_order=8, sh_basis_type=None):
"""Fits the model to data and computes peaks and metrics
Parameters
----------
model : a model instance
`model` will be used to fit the data.
sphere : Sphere
The Sphere providing discrete directions for evaluation.
relative_peak_threshold : float
Only return peaks greater than ``relative_peak_threshold * m`` where m
is the largest peak.
min_separation_angle : float in [0, 90] The minimum distance between
directions. If two peaks are too close only the larger of the two is
returned.
mask : array, optional
If `mask` is provided, voxels that are False in `mask` are skipped and
no peaks are returned.
return_odf : bool
If True, the odfs are returned.
return_sh : bool
If True, the odf as spherical harmonics coefficients is returned
gfa_thr : float
Voxels with gfa less than `gfa_thr` are skipped, no peaks are returned.
normalize_peaks : bool
If true, all peak values are calculated relative to `max(odf)`.
sh_order : int, optional
Maximum SH order in the SH fit. For `sh_order`, there will be
``(sh_order + 1) * (sh_order + 2) / 2`` SH coefficients (default 8).
sh_basis_type : {None, 'mrtrix', 'fibernav'}
``None`` for the default dipy basis which is the fibernav basis,
``mrtrix`` for the MRtrix basis, and
``fibernav`` for the FiberNavigator basis
Returns
-------
pam : PeaksAndMetrics
an object with ``gfa``, ``peak_values``, ``peak_indices``, ``odf``,
``shm_coeffs`` as attributes
"""
data_flat = data.reshape((-1, data.shape[-1]))
size = len(data_flat)
if mask is None:
mask = np.ones(size, dtype='bool')
else:
mask = mask.ravel()
if len(mask) != size:
raise ValueError("mask is not the same size as data")
npeaks = 5
sh_smooth=0
gfa_array = np.zeros(size)
qa_array = np.zeros((size, npeaks))
peak_values = np.zeros((size, npeaks))
peak_indices = np.zeros((size, npeaks), dtype='int')
peak_indices.fill(-1)
if return_sh:
#import here to avoid circular imports
from dipy.reconst.shm import sph_harm_lookup, smooth_pinv
sph_harm_basis = sph_harm_lookup.get(sh_basis_type)
if sph_harm_basis is None:
raise ValueError("Invalid basis name.")
B, m, n = sph_harm_basis(sh_order, sphere.theta, sphere.phi)
L = -n * (n + 1)
invB = smooth_pinv(B, np.sqrt(sh_smooth) * L)
n_shm_coeff = (sh_order + 2) * (sh_order + 1) / 2
shm_coeff = np.zeros((size, n_shm_coeff))
invB = invB.T
#sh = np.dot(sf, invB.T)
if return_odf:
odf_array = np.zeros((size, len(sphere.vertices)))
global_max = -np.inf
for i, sig in enumerate(data_flat):
if not mask[i]:
continue
odf = model.fit(sig).odf(sphere)
if return_sh:
shm_coeff[i] = np.dot(odf, invB)
if return_odf:
odf_array[i] = odf
gfa_array[i] = gfa(odf)
if gfa_array[i] < gfa_thr:
global_max = max(global_max, odf.max())
continue
# Get peaks of odf
_, pk, ind = peak_directions(odf, sphere, relative_peak_threshold,
min_separation_angle)
# Calculate peak metrics
global_max = max(global_max, pk[0])
n = min(npeaks, len(pk))
qa_array[i, :n] = pk[:n] - odf.min()
if normalize_peaks:
peak_values[i, :n] = pk[:n] / pk[0]
else:
peak_values[i, :n] = pk[:n]
peak_indices[i, :n] = ind[:n]
shape = data.shape[:-1]
gfa_array = gfa_array.reshape(shape)
qa_array = qa_array.reshape(shape + (npeaks,)) / global_max
peak_values = peak_values.reshape(shape + (npeaks,))
peak_indices = peak_indices.reshape(shape + (npeaks,))
pam = PeaksAndMetrics()
pam.peak_values = peak_values
pam.peak_indices = peak_indices
pam.gfa = gfa_array
pam.qa = qa_array
if return_sh:
pam.shm_coeff = shm_coeff.reshape(shape + (n_shm_coeff,))
pam.invB = invB
else:
pam.shm_coeff = None
pam.invB = None
if return_odf:
pam.odf = odf_array.reshape(shape + odf_array.shape[-1:])
else:
pam.odf = None
return pam
def main():
params = readArgs()
# read in from the command line
read_args = params.collect_args()
params.check_args(read_args)
# get img obj
dwi_img = nib.load(params.dwi_)
mask_img = nib.load(params.mask_)
from dipy.io import read_bvals_bvecs
bvals, bvecs = read_bvals_bvecs(params.bval_, params.bvec_)
# need to create the gradient table yo
from dipy.core.gradients import gradient_table
gtab = gradient_table(bvals, bvecs, b0_threshold=25)
# get the data from image objects
dwi_data = dwi_img.get_data()
mask_data = mask_img.get_data()
# and get affine
img_affine = dwi_img.affine
from dipy.data import get_sphere
sphere = get_sphere('repulsion724')
from dipy.segment.mask import applymask
dwi_data = applymask(dwi_data, mask_data)
printfl('dwi_data.shape (%d, %d, %d, %d)' % dwi_data.shape)
printfl('\nYour bvecs look like this:{0}'.format(bvecs))
printfl('\nYour bvals look like this:{0}\n'.format(bvals))
from dipy.reconst.shm import anisotropic_power, sph_harm_lookup, smooth_pinv, normalize_data
from dipy.core.sphere import HemiSphere
smooth = 0.0
normed_data = normalize_data(dwi_data, gtab.b0s_mask)
normed_data = normed_data[..., np.where(1 - gtab.b0s_mask)[0]]
from dipy.core.gradients import gradient_table_from_bvals_bvecs
gtab2 = gradient_table_from_bvals_bvecs(
gtab.bvals[np.where(1 - gtab.b0s_mask)[0]],
gtab.bvecs[np.where(1 - gtab.b0s_mask)[0]])
signal_native_pts = HemiSphere(xyz=gtab2.bvecs)
sph_harm_basis = sph_harm_lookup.get(None)
Ba, m, n = sph_harm_basis(params.sh_order_, signal_native_pts.theta,
signal_native_pts.phi)
L = -n * (n + 1)
invB = smooth_pinv(Ba, np.sqrt(smooth) * L)
# fit SH basis to DWI signal
normed_data_sh = np.dot(normed_data, invB.T)
# power map call
printfl("fitting power map")
pow_map = anisotropic_power(normed_data_sh,
norm_factor=0.00001,
power=2,
non_negative=True)
pow_map_img = nib.Nifti1Image(pow_map.astype(np.float32), img_affine)
# make output name
out_name = ''.join(
[params.output_, '_powMap_sh',
str(params.sh_order_), '.nii.gz'])
printfl("writing power map to: {}".format(out_name))
nib.save(pow_map_img, out_name)
def peaks_from_model(model,
data,
sphere,
relative_peak_threshold,
min_separation_angle,
mask=None,
return_odf=False,
return_sh=True,
gfa_thr=0,
normalize_peaks=False,
sh_order=8,
sh_basis_type=None):
"""Fits the model to data and computes peaks and metrics
Parameters
----------
model : a model instance
`model` will be used to fit the data.
sphere : Sphere
The Sphere providing discrete directions for evaluation.
relative_peak_threshold : float
Only return peaks greater than ``relative_peak_threshold * m`` where m
is the largest peak.
min_separation_angle : float in [0, 90] The minimum distance between
directions. If two peaks are too close only the larger of the two is
returned.
mask : array, optional
If `mask` is provided, voxels that are False in `mask` are skipped and
no peaks are returned.
return_odf : bool
If True, the odfs are returned.
return_sh : bool
If True, the odf as spherical harmonics coefficients is returned
gfa_thr : float
Voxels with gfa less than `gfa_thr` are skipped, no peaks are returned.
normalize_peaks : bool
If true, all peak values are calculated relative to `max(odf)`.
sh_order : int, optional
Maximum SH order in the SH fit. For `sh_order`, there will be
``(sh_order + 1) * (sh_order + 2) / 2`` SH coefficients (default 8).
sh_basis_type : {None, 'mrtrix', 'fibernav'}
``None`` for the default dipy basis which is the fibernav basis,
``mrtrix`` for the MRtrix basis, and
``fibernav`` for the FiberNavigator basis
Returns
-------
pam : PeaksAndMetrics
an object with ``gfa``, ``peak_values``, ``peak_indices``, ``odf``,
``shm_coeffs`` as attributes
"""
data_flat = data.reshape((-1, data.shape[-1]))
size = len(data_flat)
if mask is None:
mask = np.ones(size, dtype='bool')
else:
mask = mask.ravel()
if len(mask) != size:
raise ValueError("mask is not the same size as data")
npeaks = 5
sh_smooth = 0
gfa_array = np.zeros(size)
qa_array = np.zeros((size, npeaks))
peak_values = np.zeros((size, npeaks))
peak_indices = np.zeros((size, npeaks), dtype='int')
peak_indices.fill(-1)
if return_sh:
#import here to avoid circular imports
from dipy.reconst.shm import sph_harm_lookup, smooth_pinv
sph_harm_basis = sph_harm_lookup.get(sh_basis_type)
if sph_harm_basis is None:
raise ValueError("Invalid basis name.")
B, m, n = sph_harm_basis(sh_order, sphere.theta, sphere.phi)
L = -n * (n + 1)
invB = smooth_pinv(B, np.sqrt(sh_smooth) * L)
n_shm_coeff = (sh_order + 2) * (sh_order + 1) / 2
shm_coeff = np.zeros((size, n_shm_coeff))
invB = invB.T
#sh = np.dot(sf, invB.T)
if return_odf:
odf_array = np.zeros((size, len(sphere.vertices)))
global_max = -np.inf
for i, sig in enumerate(data_flat):
if not mask[i]:
continue
odf = model.fit(sig).odf(sphere)
if return_sh:
shm_coeff[i] = np.dot(odf, invB)
if return_odf:
odf_array[i] = odf
gfa_array[i] = gfa(odf)
if gfa_array[i] < gfa_thr:
global_max = max(global_max, odf.max())
continue
# Get peaks of odf
_, pk, ind = peak_directions(odf, sphere, relative_peak_threshold,
min_separation_angle)
# Calculate peak metrics
global_max = max(global_max, pk[0])
n = min(npeaks, len(pk))
qa_array[i, :n] = pk[:n] - odf.min()
if normalize_peaks:
peak_values[i, :n] = pk[:n] / pk[0]
else:
peak_values[i, :n] = pk[:n]
peak_indices[i, :n] = ind[:n]
shape = data.shape[:-1]
gfa_array = gfa_array.reshape(shape)
qa_array = qa_array.reshape(shape + (npeaks, )) / global_max
peak_values = peak_values.reshape(shape + (npeaks, ))
peak_indices = peak_indices.reshape(shape + (npeaks, ))
pam = PeaksAndMetrics()
pam.peak_values = peak_values
pam.peak_indices = peak_indices
pam.gfa = gfa_array
pam.qa = qa_array
if return_sh:
pam.shm_coeff = shm_coeff.reshape(shape + (n_shm_coeff, ))
pam.invB = invB
else:
pam.shm_coeff = None
pam.invB = None
if return_odf:
pam.odf = odf_array.reshape(shape + odf_array.shape[-1:])
else:
pam.odf = None
return pam
def peaks_from_model(model, data, sphere, relative_peak_threshold,
min_separation_angle, mask=None, return_odf=False,
return_sh=True, gfa_thr=0, normalize_peaks=False,
sh_order=8, sh_basis_type=None, ravel_peaks=False,
npeaks=5, parallel=False, nbr_process=None):
"""Fits the model to data and computes peaks and metrics
Parameters
----------
model : a model instance
`model` will be used to fit the data.
sphere : Sphere
The Sphere providing discrete directions for evaluation.
relative_peak_threshold : float
Only return peaks greater than ``relative_peak_threshold * m`` where m
is the largest peak.
min_separation_angle : float in [0, 90] The minimum distance between
directions. If two peaks are too close only the larger of the two is
returned.
mask : array, optional
If `mask` is provided, voxels that are False in `mask` are skipped and
no peaks are returned.
return_odf : bool
If True, the odfs are returned.
return_sh : bool
If True, the odf as spherical harmonics coefficients is returned
gfa_thr : float
Voxels with gfa less than `gfa_thr` are skipped, no peaks are returned.
normalize_peaks : bool
If true, all peak values are calculated relative to `max(odf)`.
sh_order : int, optional
Maximum SH order in the SH fit. For `sh_order`, there will be
``(sh_order + 1) * (sh_order + 2) / 2`` SH coefficients (default 8).
sh_basis_type : {None, 'mrtrix', 'fibernav'}
``None`` for the default dipy basis which is the fibernav basis,
``mrtrix`` for the MRtrix basis, and
``fibernav`` for the FiberNavigator basis
ravel_peaks : bool
If True, the peaks are returned as [x1, y1, z1, ..., xn, yn, zn] instead
of Nx3. Set this flag to True if you want to visualize the peaks in the
fibernavigator or in mrtrix.
npeaks : int
Maximum number of peaks found (default 5 peaks).
parallel: bool
If True, use multiprocessing to compute peaks and metric (default False).
nbr_process: int
If `parallel == True`, the number of subprocess to use (default multiprocessing.cpu_count()).
Returns
-------
pam : PeaksAndMetrics
An object with ``gfa``, ``peak_directions``, ``peak_values``,
``peak_indices``, ``odf``, ``shm_coeffs`` as attributes
"""
if parallel:
return __peaks_from_model_parallel(model,
data, sphere,
relative_peak_threshold,
min_separation_angle,
mask, return_odf,
return_sh,
gfa_thr,
normalize_peaks,
sh_order,
sh_basis_type,
ravel_peaks,
npeaks,
nbr_process)
shape = data.shape[:-1]
if mask is None:
mask = np.ones(shape, dtype='bool')
else:
if mask.shape != shape:
raise ValueError("Mask is not the same shape as data.")
sh_smooth = 0
gfa_array = np.zeros(shape)
qa_array = np.zeros((shape + (npeaks,)))
peak_dirs = np.zeros((shape + (npeaks, 3)))
peak_values = np.zeros((shape + (npeaks,)))
peak_indices = np.zeros((shape + (npeaks,)), dtype='int')
peak_indices.fill(-1)
if return_sh:
# import here to avoid circular imports
from dipy.reconst.shm import sph_harm_lookup, smooth_pinv
sph_harm_basis = sph_harm_lookup.get(sh_basis_type)
if sph_harm_basis is None:
raise ValueError("Invalid basis name.")
B, m, n = sph_harm_basis(sh_order, sphere.theta, sphere.phi)
L = -n * (n + 1)
invB = smooth_pinv(B, np.sqrt(sh_smooth) * L)
n_shm_coeff = (sh_order + 2) * (sh_order + 1) / 2
shm_coeff = np.zeros((shape + (n_shm_coeff,)))
invB = invB.T
if return_odf:
odf_array = np.zeros((shape + (len(sphere.vertices),)))
global_max = -np.inf
for idx in ndindex(shape):
if not mask[idx]:
continue
odf = model.fit(data[idx]).odf(sphere)
if return_sh:
shm_coeff[idx] = np.dot(odf, invB)
if return_odf:
odf_array[idx] = odf
gfa_array[idx] = gfa(odf)
if gfa_array[idx] < gfa_thr:
global_max = max(global_max, odf.max())
continue
# Get peaks of odf
direction, pk, ind = peak_directions(
odf, sphere, relative_peak_threshold,
min_separation_angle)
# Calculate peak metrics
global_max = max(global_max, pk[0])
n = min(npeaks, len(pk))
qa_array[idx][:n] = pk[:n] - odf.min()
peak_dirs[idx][:n] = direction[:n]
peak_indices[idx][:n] = ind[:n]
peak_values[idx][:n] = pk[:n]
if normalize_peaks:
peak_values[idx][:n] /= pk[0]
peak_dirs[idx] *= peak_values[idx][:, None]
#gfa_array = gfa_array
qa_array /= global_max
#peak_values = peak_values
#peak_indices = peak_indices
# The fibernavigator only supports float32. Since this form is mainly
# for external visualisation, we enforce float32.
if ravel_peaks:
peak_dirs = peak_dirs.reshape(shape + (3 * npeaks,)).astype('float32')
pam = PeaksAndMetrics()
pam.peak_dirs = peak_dirs
pam.peak_values = peak_values
pam.peak_indices = peak_indices
pam.gfa = gfa_array
pam.qa = qa_array
if return_sh:
pam.shm_coeff = shm_coeff
pam.invB = invB
else:
pam.shm_coeff = None
pam.invB = None
if return_odf:
pam.odf = odf_array
else:
pam.odf = None
return pam