[Insight-users] time of non rigid registation.

[Torsten Rohlfing]

Hi Guys --

Just a quick note: there is no such thing as "Rohlfing's B-spline based 
registration", and I should know ;)

Seriously -- there is "Rueckert's B-spline registration" (as per his 
1999 IEEE-TMI paper) as an ALGORITHM, and there is "Rohlfing's 
implementation of Rueckert's algorithm" as a PIECE OF CODE (which, 
coincidentally is not related to the piece of code in ITK).

Everything else I guess Luis has already answered.

Best,
  Torsten

Tao, Guozhi wrote:
> Hi, Luis:
> Thanks for your reply. Can you further tell  me your impression that the time for Demons' algorithm and Rohlfing's  B spline based registration (3 mm control knots) seperately  to register  256*256*128  volume. More specicely, I like to know the ratio of regstration time for those two algorithm.
>  
> Best wishes
> Guozhi 
>
> ________________________________
>
> From: Luis Ibanez [mailto:luis.ibanez at kitware.com]
> Sent: Thu 6/21/2007 6:01 PM
> To: Tao, Guozhi 
> Cc: Torsten Rohlfing; insight-users at itk.org
> Subject: Re: [Insight-users] time of non rigid registation.
>
>
>
>
> Hi Guozhi,
>
> For that image size you should expect between 30min and 1hour.
>
> Note, that the registration time depends on many factors,
> including, how much actual misalignment there is originally
> between the two images.
>
>
>    Regards,
>
>
>       Luis
>
>
> ---------------------
> Tao, Guozhi wrote:
>   
>> Hi:
>> Can sombody tell me how long the nonrigid registration algorithm in ITK need to register 256*256*128 volume on current pentium4 pc. I want to know the time consuming for Demons algorithm and BSplineDeformableTransform. Just roughtly estimation by your experience is fine.
>> best wishes
>> Guozhi Tao
>>
>>
>> ________________________________
>>
>> From: insight-users-bounces+guozhi.tao=uth.tmc.edu at itk.org on behalf of Torsten Rohlfing
>> Sent: Thu 6/14/2007 11:15 AM
>> To: insight-users at itk.org
>> Subject: [Insight-users] a question about rigid + nonrigid registration
>>
>>
>>
>>
>>     
>>> I am currently trying to register two volumes. One volume only contains part
>>> of the other, so I used the larger volume as fixed image and smaller volume
>>> as the moving image.  First, I performed a rigid
>>> registration(VersorRigid3DTransform) and then want to fine tune the
>>> rigistration by nonrigid method (BSplineDeformableTransform). However, I do
>>> not know how to initialize the  BSplineDeformableTransform using the
>>> existing rigid result (VersorRigid3DTransform). Maybe I can use resample
>>> filter to get a new moving image based on the rigid registration. But the
>>> resampled moving image has the size of the larger volume, so some voxels do
>>> not have resampled value and this will cause problems in further nonrigid
>>> registration. Hope I made my questions clear.
>>>
>>> Qing
>>>
>>>       
>> Hi --
>>
>> Indeed, resampling the moving image after affine and before nonrigid
>> registration is not a good idea, both for the reason you mentioned (loss
>> of field of view boundaries) and because interpolation artifacts can
>> build up from stage to stage.
>>
>> What you need to do is take your rigid transformation and set it as the
>> "Bulk Transform" in the B-spline transformation object. That's all.
>> Please consult the online documentation for the exact name of the member
>> function in BSplineDeformableTransform.
>>
>> Best,
>>   Torsten
>>
>> --
>> Torsten Rohlfing, PhD          SRI International, Neuroscience Program
>>  Research Scientist             333 Ravenswood Ave, Menlo Park, CA 94025
>>   Phone: ++1 (650) 859-3379      Fax: ++1 (650) 859-2743
>>    torsten at synapse.sri.com        http://www.stanford.edu/~rohlfing/
>>
>>      "Though this be madness, yet there is a method in't"
>>
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>>     
>
>
>   


-- 
Torsten Rohlfing, PhD          SRI International, Neuroscience Program
 Research Scientist             333 Ravenswood Ave, Menlo Park, CA 94025
  Phone: ++1 (650) 859-3379      Fax: ++1 (650) 859-2743
   torsten at synapse.sri.com        http://www.stanford.edu/~rohlfing/

     "Though this be madness, yet there is a method in't"