Tool for performing variable transformations. ANTS (Advanced Normalization Tools) package is designed to enable researchers with advanced tools for brain and image mapping. Many of the ANTS registration tools are diffeomorphic*, but deformation (elastic and BSpline) transformations are available. Unique components of ANTS include multivariate similarity metrics, landmark guidance, the ability to use label images to guide the mapping and both greedy and space-time optimal implementations of diffeomorphisms. The symmetric normalization (SyN) strategy is a part of the ANTS toolkit as is directly manipulated free form deformation (DMFFD).

ANTS Features:
1. Save state of registration so that it can be reinitialized later: B.A.
2. Constrain x, y or z deformation to be zero - also in metric computation
3. Massive speed up in CC metric - fixed Mutual Information (MI) metric
4. Finalize Atropos + give examples
5. Warp Time Series Image

Example usage:
ANTS.exe ImageDimension -m MI[fixedimage.nii.gz,movingimage.nii.gz,1,32] -o Outputfname.nii.gz -i 30x20x0 -r Gauss[3,1] -t Elast[3]

Compulsory arguments:
ImageDimension: 2 or 3 (for 2 or 3 Dimensional registration)
-m: Type of similarity model used for registration.
For intramodal image registration, use:
CC = cross-correlation
MI = mutual information
PR = probability mapping
MSQ = mean square difference

For intermodal image registration, use:
MI = mutual information
PR = probability mapping

-o Outputfname.nii.gz: the name of the resulting image.
-i Max-iterations in format: JxKxL, where:
J = max iterations at coarsest resolution (here, reduce by power of 2^2)
K = middle resolution iterations (here,reduce by power of 2)
L = fine resolution iterations (here, full resolution). This level takes much more time per iteration!

Adding an extra value before JxKxL (i.e. resulting in IxJxKxL) would add another iteration level.
-r Regularization
-t Type of transformation model used for registration

For elastic image registration, use:
Elast = elastic transformation model (less deformation possible)

For diffeomorphic image registration, use:
1. Syn[GradStep,TimePoints,IntegrationStep] --geodesic 2 = SyN with time with arbitrary number of time points in time discretization
2. SyN[GradStep,2,IntegrationStep] = SyN with time optimized specifically for 2 time points in the time discretization
3. SyN[GradStep] = Greedy SyN, typicall GradStep=0.25
4. Exp[GradStep,TimePoints] = Exponential
5. GreedyExp = Diffeomorphic Demons style exponential mapping

The license of this software is Free, you can free download and free use this application software.