[Insight-users] Regularization terms for registration algorithms

[Luis Ibanez]

Hi Rosario,

There are multiple implementations of Deformable Registration
methods in ITK. All of them include some type of regularization
of the deformation field.



They are:


1) Demons : PDE implementation. Regularization is done by applying
             Gaussian Smoothing to the deformation field at every
             iteration of the PDE solver.


2) BSplines : Generic registration framework. Regularization is
             provided by the interpolation properties of BSplines.
             The amount of regularization will be related to the
             number of nodes in the BSpline grid and to the degree
             of the BSpline that you chose to use.


3) Finite Element Methods (FEM). The image is modeled as a physical
             block of material with some elasticity properties.
             Regularization is provided by the simulation of physical
             properties in the material, and by the degree of the shape
             functions used to interpolate the displacement fields.


4) LevelSets. In this method one image is deformed by using forces
             generated from the other image. The degree of regularization
             is related to the Curvature weight of the level set.



For more details you may want to read the ITK Software Guide:


           http://www.itk.org/ItkSoftwareGuide.pdf


and the Tutorials:


       http://www.itk.org/HTML/Tutorials.htm


in particular the session on Deformable Registration:


http://www.itk.org/CourseWare/Training/NonRigidRegistrationMethods.pdf





    Regards,



        Luis




---------------------
Rosario Sance wrote:
> 
> Hi everybody,
> 
> At the moment I´m dealing with 3D non-rigid registration. I´ve heard 
> about the use of *regularization terms *to favor the smoothness of the 
> deformation. That idea could be found, for example, in the paper:
> 
> Carlos O. S. Sorzano, Philippe Thévenaz and Michael Unser, /Elastic 
> Registration of Biological Images Using Vector-Spline Regularization/, 
> IEEE Transactions On Biomedical Engineering, Vol.52, Nº4, April 2005.
> 
> What I´d like to know is if there is something like that already 
> implemented in ITK. Previous similar questions have been posed before in 
> the users list but without response.
> 
> Could anybody help me?
> Thanks a lot in advance.
> 
> Regards,
> Rosario
> 
> 
> 
> 
> Rosario Sance Garzón
> Dpto. Ingeniería Electrónica
> E.T.S.I. Telecomunicación
> Avda. Ciudad Universitaria s/n
> E-28040 - Madrid (SPAIN)
> ___________________________________________________
> 
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