Align two volumes using an affine and, optionally, SDR.
SpatialImage
The image to morph (“from” volume).
SpatialImage
The image to align with (“to” volume).
str
| tuple
The volume registration steps to perform (a str
for a single step,
or tuple
for a set of sequential steps). The following steps can be
performed, and do so by matching mutual information between the images
(unless otherwise noted):
'translation'
Translation.
'rigid'
Rigid-body, i.e., rotation and translation.
'affine'
A full affine transformation, which includes translation, rotation, scaling, and shear.
'sdr'
Symmetric diffeomorphic registration [1], a non-linear similarity-matching algorithm.
The following string shortcuts can also be used:
'all'
(default)All steps will be performed above in the order above, i.e.,
('translation', 'rigid', 'affine', 'sdr')
.
'rigids'
The rigid steps (first two) will be performed, which registers
the volume without distorting its underlying structure, i.e.,
('translation', 'rigid')
. This is useful for
example when registering images from the same subject, such as
CT and MR images.
'affines'
The affine steps (first three) will be performed, i.e., omitting the SDR step.
float
| tuple
| dict
| None
The voxel size of volume for each spatial dimension in mm.
If None (default), MRIs won’t be resliced (slow, but most accurate).
Can be a tuple to provide separate zooms for each dimension (X/Y/Z),
or a dict with keys ['translation', 'rigid', 'affine', 'sdr']
(each with values that are float`, tuple, or None) to provide separate
reslicing/accuracy for the steps.
dict
| tuple
| None
For each phase of the volume registration, niter
is the number of
iterations per successive stage of optimization. If a tuple is
provided, it will be used for all steps (except center of mass, which does
not iterate). It should have length 3 to
correspond to sigmas=[3.0, 1.0, 0.0]
and factors=[4, 2, 1]
in
the pipeline (see dipy.align.affine_registration
for details).
If a dictionary is provided, number of iterations can be set for each
step as a key. Steps not in the dictionary will use the default value.
The default (None) is equivalent to:
- niter=dict(translation=(100, 100, 10),
rigid=(100, 100, 10), affine=(100, 100, 10), sdr=(5, 5, 3))
str
| int
| None
Control verbosity of the logging output. If None
, use the default
verbosity level. See the logging documentation and
mne.verbose()
for details. Should only be passed as a keyword
argument.
ndarray
of float
, shape (4, 4)The affine that registers one volume to another.
dipy.align.DiffeomorphicMap
The class that applies the the symmetric diffeomorphic registration (SDR) morph.
Notes
This function is heavily inspired by and extends
dipy.align.affine_registration
.
New in version 0.24.
mne.transforms.compute_volume_registration
#Locating intracranial electrode contacts