[Insight-users] Volume registration using position vectors -- newbie question

[Luis Ibanez]

Hi Frank,

Since your two images are relating to the same scanner,
you should be ok by simply using an IdentityTransform:

http://www.itk.org/Insight/Doxygen/html/classitk_1_1IdentityTransform.html


Note that the itk::IdentityTransform class doesn't take any parameters.
Simply create one instance of this transform connect it to the
itk::ResampleImageFilter.



   Regards,



       Luis



------------------------
Frank Ezekiel wrote:
> Any hints on how to initialize the transform that will be used?
> 
> finalTransform->SetParameters( finalParameters );
> 
> 
> How do I set up the transform object to properly do the "difference" 
> between the orientation and translation parameters?
> 
> Thanks again,
> Frank
> 
> 
> 
>  At 08:15 AM 10/6/2007, you wrote:
> 
>> Hi Frank,
>>
>> From your description it seems that you only need to resample
>> image B using the grid of image A.
>>
>> That is, you are relying on the fact that both images have been
>> acquired from the same scanner, and that the image origing and
>> direction cosines are correct.
>>
>> That should work fine.
>>
>> Just remember to use the itk::OrientedImage<> instead of the
>> itk::Image.
>>
>> The itk::OrientedImage will take the Direction cosines into
>> account when it is used by the interpolator of the Resample
>> ImageFilter.
>>
>>
>> Please read the ITK Software Guide,
>>
>>      http://www.itk.org/ItkSoftwareGuide.pdf
>>
>> in particular Section 6.9.4 "Resample Image Filter" in
>> pdf-pages 254-448.
>>
>> This section describes in detail how to use the ResampleImageFilter.
>>
>>
>>    Regards,
>>
>>
>>       Luis
>>
>>
>>
>> -----------------------
>> Frank Ezekiel wrote:
>>
>>> Luis:
>>>         Thank you for the initial response.     At this point, my 
>>> goal has changed slightly.   I'm looking to use ITK to write a 
>>> function that will align MovingImage to FixedImage WITHOUT any 
>>> intensity based registration.
>>>         That is, I want to use ONLY the DCM (direction cosine matrix) 
>>> and coordinate offset data included in a dicom header.
>>>         (The reason is that my FixedImage space is from single voxel 
>>> spectroscopy, so there is inadequate intensity information to use a 
>>> cost function + resampling for alignment.)
>>>         Can ITK do this?     It basically just requires computing and 
>>> applying the "difference transformation" between two images acquired 
>>> in the same session.
>>>
>>> Thanks again for the help,
>>> Frank
>>>
>>>
>>> At 07:34 AM 8/5/2007, Luis Ibanez wrote:
>>>
>>>> Hi Frank,
>>>>
>>>>
>>>> You may want to start with the example:
>>>>
>>>>
>>>>       ImageRegistration8.cxx
>>>>
>>>>
>>>> in the directory:
>>>>
>>>>
>>>>       Insight/Examples/Registration
>>>>
>>>>
>>>> This example is described in detail in the
>>>> ITK Software Guide
>>>>
>>>>    http://www.itk.org/ItkSoftwareGuide.pdf
>>>>
>>>> in the "Image Registration" chapter.
>>>>
>>>>
>>>> We *STRONGLY* recommend you to read the entire chapter
>>>> before you start playing with the registration. You
>>>> should also read the Section on image resampling since
>>>> they are very closely related.
>>>>
>>>> Since your images seems to be from the same modality
>>>> and same patient, you can probably solve this by using
>>>> the following components:
>>>>
>>>>   1) Mean Squares Metric
>>>>   2) VersorRigid3D Transform
>>>>   3) Linear Interpolator
>>>>   4) VersorRigid3DTransformOptimizer
>>>>
>>>> Note that, since you are reading this from DICOM,
>>>> you want to replace the "itk::Image" type in the
>>>> code with "itk::OrientedImage" type, in order to
>>>> make sure that the direction cosines of your images
>>>> are taken into account.
>>>>
>>>> ---
>>>>
>>>> Examples on how to read DICOM series are available
>>>> in the directory:
>>>>
>>>>
>>>>            Insight/Examples/IO
>>>>
>>>> and are described as well in the ITK Software Guide
>>>> in the Chapter "Reading and Writing Images".
>>>>
>>>>
>>>> Please let us know if you find any problems
>>>> while setting up your registration code.
>>>>
>>>>
>>>>
>>>> Regards,
>>>>
>>>>
>>>>    Luis
>>>>
>>>>
>>>> --------------------
>>>> Frank Ezekiel wrote:
>>>>
>>>>> Hi:
>>>>>     I have multiple MRI acquisitions acquired on Siemens Medspec 4T 
>>>>> and stored in Dicom.   I'm looking for the quickest and easiest way 
>>>>> to compute the rotations and translations needed to align one 
>>>>> dataset with the other (assuming no movement).
>>>>>     Could someone please enumerate my options within ITK for doing 
>>>>> this?    I really just want a robust readout of angles and mm 
>>>>> translations given Dicom 3.0 files with tags (0020,0032) and 
>>>>> (0020,0037) filled in.
>>>>>     Suggestions?
>>>>> Thanks mucho,
>>>>> Frank
>>>>> _______________________________________________
>>>>> Insight-users mailing list
>>>>> Insight-users at itk.org
>>>>> http://www.itk.org/mailman/listinfo/insight-users
> 
>