[ITK Community] Regularity term in deformable registration ITK

[Luis Ibanez]

Hi Hana,

Deformable registration is always an ill-posed problem,
given that there are always a multiplicity of solutions.

The regularity terms help drive the optimizers towards a
subset of solutions that produce smooth displacement
fields.  They are, however, not specific enough as to
produce a "correct" answer.

The goal with a deformable registration process, is to find
a displacement field that is "good enough" for a particular
application.

There is no real "right" nor "correct" answer to be found.


     Best,


         Luis



On Sun, Feb 9, 2014 at 9:42 AM, Hana Cherif <hanacherif62 at gmail.com> wrote:

> Hello again ,,
>
> I mean all the things that you  have mentioned, but how about the
> numerical validation of this property!! I know that the regularity term
> imposes to the deformation field to be smooth, and it making the problem
> well posed no???  If what i say is true,,  haw did this points verified in
> that model in ITK because i saw that only the similarity term was
> implemented !!
>
> Hope that it is clear!!
>
> Best regards !!
>
>
>
>
> 2014-02-08 23:25 GMT+01:00 Luis Ibanez <luis.ibanez at kitware.com>:
>
> Hi Hana,
>>
>> When you ask about the "verification of the regularity of the solution",
>>
>> are you thinking about inspection of the deformation field ?
>> maybe about visualization of the deformation field ?
>>
>> or are you thinking about a more formal numerical validation ?
>>
>>   Thanks
>>
>>       Luis
>>
>>
>>
>> On Sat, Feb 8, 2014 at 3:47 PM, Hana Cherif <hanacherif62 at gmail.com>wrote:
>>
>>> Hello all ,,
>>>
>>> Another question please about the smoothness term (regularity term )
>>>
>>> We know all that the image registration's methods implemented in ITK
>>> based on a variational approach ,, which serves to minimize an energy
>>> includes two terms : similarity term which measure similarities of the two
>>> images, and a regularity term which ensure the regularity of that
>>> transformation. For me this two terms are essential, mainly  in the
>>> processes of deformable registration !! My question is how did the
>>> regularity of the solution is verified in the model proposed in ITK ,, i
>>> mean the BSpline registration (DeformableRegistration4)
>>>
>>> Thanks in advance!!
>>>
>>> Hana
>>>
>>>
>>> _______________________________________________
>>> Community mailing list
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>>>
>>>
>>
>
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