[Insight-users] "throwing exception at StartRegistration()"

[Luis Ibanez]

Hi Jorn,

This error happens when the fixed image and moving image
are no longer overlapped. This is an indication that the
transform is completely off position.

Typically this happens when the translation component of
the transform is larger than the image size. You can verify
this by looking at the transform parameters. If you are using
an Affine transform in 3D, the last three parameters are
translations.


Here are some options you may want to consider:

0) Verify that the origin and spacing of both image
    are correctly set up. Registration is performed in
    physical space coordinates, not in pixels. Inconsitent
    pixel spacing may generate too large translations in
    the transform.

1) Reduce the learning rate of the optimizer in order
    to force smaller steps.

2) Modify the translation scale parameter. This parameter
    controls how fast the optimizer advance on rotations
    vs translations.

3) Track the evolution of parameters in order to identify
    when the transform is getting out of range. Use a
    Command / Observer for this purpose.



    Luis



=========================================================

J. Van Dalen wrote:

> Dear CSPL,
> 
> I try to perform a registration using Mutual information and I encouter
> a similar error as you did encounter a few months ago.
> 
>>From the The Insight-users Archives I found:
> 
>>I am working on MRI Registration.I have made my own project using MRI
>>Registration example available in ITK examples.It is working well for
>>some MRI images.But,It is throwing exception at StartRegistration() for
>>some imagess.I have hard coded the Parameters which I have to set
>>before calling StartRegistration().Plese, help me in solving my
>>problem and give me some information on setting parameter values. Here
>>I am enclosing the code and parameters details.I am also enclosing the
>>exception message thrown by startregistration().
>>
>>//Exception message
>>itk::ERROR: MutualInformationImageToImageMetric(003C6D20): All the
>>sampled point mapped to outside of the moving image
>>
> 
> Now, I have exactly the same error as you had that time. And your code
> looks very similar to my code. Did you find a solution to this problem?
> Or, do you know why you had this error?
> 
> Hope you can help me,
> Thanks and Regards,
> Jorn.
> 
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