static_img_files : string
Path to the static image file.
moving_img_files : string
Path to the moving image file.
transform : string, optional
com: center of mass, trans: translation, rigid: rigid body
affine: full affine including translation, rotation, shearing and scaling (default ‘affine’).
nbins : int, optional
Number of bins to discretize the joint and marginal PDF
(default ‘32’).
sampling_prop : int, optional
Number ([0-100]) of voxels for calculating the PDF.
‘None’ implies all voxels (default ‘None’).
metric : string, optional
Similarity metric for gathering mutual information
(default ‘mi’ , Mutual Information metric).
level_iters : variable int, optional
The number of iterations at each scale of the scale space.

level_iters[0] corresponds to the coarsest scale, level_iters[-1] the finest, where n is the length of the

sequence. By default, a 3-level scale space with iterations sequence equal to [10000, 1000, 100] will be used.
sigmas : variable floats, optional
Custom smoothing parameter to build the scale space (one parameter
for each scale). By default, the sequence of sigmas will be [3, 1, 0].
factors : variable floats, optional
Custom scale factors to build the scale space (one factor for each
scale). By default, the sequence of factors will be [4, 2, 1].
progressive : boolean, optional
Enable/Disable the progressive registration (default ‘True’).
save_metric : boolean, optional
If true, quality assessment metric are saved in ‘quality_metric.txt’ (default ‘False’).
out_dir : string, optional
Directory to save the transformed image and the affine matrix
(default ‘’).
out_moved : string, optional
Name for the saved transformed image
(default ‘moved.nii.gz’).
out_affine : string, optional
Name for the saved affine matrix
(default ‘affine.txt’).
out_quality : string, optional
Name of the file containing the saved quality
metric (default ‘quality_metric.txt’).