[Insight-users] Need help regarding registration techniques (ITK newbie :) )

[Karthik Krishnan]

On Thu, Aug 20, 2009 at 4:28 AM, Balaji, R IN BLR SISL <r.balaji at siemens.com
> wrote:

> Can you please advice on which algo will be suitable and if possible the
> reason behind the time taken by the B-Spline algo ?
>

Balaji:

Yes it is quite time consuming. The following questions will help ameliorate
your situation.

- What is the resolution of the images ?

- On which image is the BSpline grid being defined PET or CT. Choosing the
lower resolution image as the fixed image is going to speed up metric
evaluation.

- What is the resolution of the grid ? This impacts speed.

- Have you turned ITK_USE_OPTIMIZED_REGISTRATION on ?

- If the answer to the previous question is yes, did you enable caching of
the BSpline transform parameters ? This provides significant speedups. See
http://www.insight-journal.org/browse/publication/172 for quantitative
experiments detailing the speedups.
  Depending on the resolution of your data and memory availability on your
machine, this may or may not be possible. Memory requirements shoot up with
caching.

- Did you take a look at multiresolution registration options. Take a look
at DeformableRegistration15.cxx . This does a coarse and fine deformable
registration and uses a BSplineDecomposition filter to initialize the fine
BSpline transform from the coarse.

- Did you take a look at rigid followed by deformable registration. Again
please look at DeformableRegistration15.cxx .

- If your registration problem can be localized to a specific region, you
could specify a fixed image region and/or fixed and moving image masks. This
will restrict the computation of the metric / and / allow you to define a
higher resolution transform within the region in question.

Hope this helps.



-- 
Karthik Krishnan
R&D Engineer,
Kitware Inc.
Ph: 518 881 4919
Fax: 518 371 4573
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.itk.org/pipermail/insight-users/attachments/20090821/e76733dd/attachment.htm>