[Insight-users] Question on TransformInitializer

[Luis Ibanez]

Hi Gerald,


1) The MaskImageFilter will do exactly what you have done,
    I just mentioned it because it could have saved you some
    programming time. (maybe for the next time you have a
    similar need).


2)  The mailing list doesn't accept emails larger than 40Kb.
     (they are supposed to be only text).

     I meant to suggest that you post the screen shots in a
     public web site, and post the URL to the list, so we can
     look at them.


 Thanks


         Luis


------------------------------------------------------------------------
On Wed, Mar 17, 2010 at 2:53 AM, Lodron, Gerald
<Gerald.Lodron at joanneum.at> wrote:
> Hi
>
> I am using itk::CenteredVersorTransformInitializer which is only implemented with momentsOn().
>
> As I told i make a binary image from my segmentation and multiplies it with the image, so the resulting image has grayvalues on the image data and zeros on background. Does the itkMaskImageFilter work different? And the result is a transformation initialization without overlap (for sure i make this with moving and fixed image). I tested this on several different CT images and the result stays the same, everytime when i multiply it with a mask the initialization fails, without multiplying it works...I also looked at the image, the segmentation and the multiplying works without porblems so the image looks as it should...
>
> I am not able to post screenshots because then my email got blocked (I already tested this several times, i always get a message that my message waits approval from the admin but never gets released). But the image is displaying a standard 3D CT data set from the top of the head to the middle of the lung (for sure centered in the image). The segmentation does only segment the patient, background is the patient table and the air outside the body.
>
> Best regards,
>
> -----Ursprüngliche Nachricht-----
> Von: Luis Ibanez [mailto:luis.ibanez at kitware.com]
> Gesendet: Dienstag, 16. März 2010 19:11
> An: Lodron, Gerald
> Cc: insight-users at itk.org
> Betreff: Re: [Insight-users] Question on TransformInitializer
>
> Hi Gerald,
>
> Are you using the VersorTransformIntializer with
>
>              GeometryOn()    ?
>
> or with
>
>              MomentsOn()    ?
>
>
> For the masking process to make sense,
> you should use it with MomentsOn().
>
> Note also that ITK has a Mask filter:
>
>          itkMaskImageFilter
>
>
> that you could use to mask your moving
> image.
>
>
> --
>
> If you still have problems, please post
> screenshots of the Fixed image and
> Moving image, as well as the following
> parameters for both images:
>
>  A) Image Origin
>  B) Image Size in pixels
>  C) Image Spacing
>  D) Image Direction ( direction cosines)
>
>
>
> Regards,
>
>
>     Luis
>
>
> ------------------------------------------
> On Fri, Mar 12, 2010 at 5:30 AM, Lodron, Gerald <Gerald.Lodron at joanneum.at> wrote:
>>
>> Hello
>>
>> I made a 3D registration of two CT data sets and use the Versor transform initializer and a image mask in my registration. The registration wroks in my most test data sets but now i want to improve the registration. I thought i could use the segmentation result also in the initializer but there is no SetMovingImageMask function in the initializer, so i first made the following: I multiplied the boolean image of the segmentation with the image before i give it to the initializer. The result of the initializer is very bad, the initial transformation transform the image so that no overlap appears. My second approach was to use the GetFixedCalculator() function of the initializer which gives me the moments calculator object back. The moments calculater has such a SetSpatialObjectMask function. The only problem is that the GetFixedCalculator() function returns a const pointer, using a const cast it compiles, but the result is the same as with multiplieing.
>>
>> Any suggestions/explanations why this does not work?
>>
>>
>>
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>