[Insight-users] some information on the registration example methods

[Luis Ibanez]

Hi Michael,


It is great to have users who
post messages when things work   !   :-)


--


About the deformable registration example,
You can reduce the computation time by
using a Multi-Resolution approach. This
particular example is using the Demons
algorithm and was implemented by Lydia Ng
at Insightful. The DemonsRegistrationFilter
derives from the generic class:

     PDEDeformableRegistrationFilter
http://www.itk.org/Insight/Doxygen/html/classitk_1_1PDEDeformableRegistrationFilter.html


The MultiResolution variant of this class is the
http://www.itk.org/Insight/Doxygen/html/classitk_1_1MultiResolutionPDEDeformableRegistration.html

What you want to do in this case is to progressively
refine the deformation field by computing first a
low resolution version of it. In this way you reduce
the time to convergence and improve the robustness
of the registration.


You will find information on the ITK registration
framework in the Software Guide:

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

In particular Chapter 8.

(you can order the paper version of this document
from Amazon.com and from Kitware's estore)
http://www.kitware.com/products/itkguide.html


You will also find details on the theory behind
algorithms implemented in ITK, in the book
"Insight into Images" published by A.K. Peters
http://www.akpeters.com/book.asp?bID=206


The tutorial session on deformable registration
presented by Dr. James Gee will also be illuminating:
http://www.itk.org/CourseWare/Training/NonRigidRegistrationMethods.pdf




Please let us know if you have further questions.



   Thanks,



     Luis



------------------------------
Michael G wrote:

> Hello,
> 
> I am using the technique in ImageRegistration1 to motion correct a set 
> of dicom images and it's working great. It takes about 3-4 seconds per 
> image.
> 
> I noticed the other great examples, specifically the 
> DeformableRegistration2, because it seems to offer even cleaner results. 
> This method is taking a great deal longer to run per slice, around 11 
> seconds on the same machine.
> 
> Are there any methods to improving the speed for these methods? Also are 
> there more resources on the science behind these registration methods 
> that itk has provided for us? I could only find
> http://www.itk.org/CourseWare/Training/RegistrationMethodsOverview.pdf
> 
> Thank you very much for any info,
> Michael
>