[Insight-users] Mattes MI: "Too many samples map outside..."

[Xabier Artaechevarria Artieda]

I agree, that is odd. In fact, the images are exactly the same size,  
and they have been registered with an affine transform previously.




Karthik Krishnan <karthik.krishnan at kitware.com> ha escrito:

> That's odd.
>
> Is the moving image a lot smaller than the fixed image ? Samples are taken
> from the fixed image. If the moving image is a lot smaller, that could
> explain their mapping outside the moving image region.
>
> -karthik
>
>
> On 2/12/07, Xabier Artaechevarria Artieda <xabiarta at unav.es> wrote:
>>
>> Hi Karthik,
>> Thanks for your answer.
>> I just set the maximum number of iterations to 174 and applied the
>> resulting transform to the moving image. Comparing it to the fixed
>> image, the overlapped seemed good.
>> I tried changing the number of spatial samples (from 1/10 to 1/9) and
>> now the registration is working fine. I must admit I do not really
>> know why.
>> Regards,
>> Xabi
>>
>>
>>
>>
>> Karthik Krishnan <karthik.krishnan at kitware.com> ha escrito:
>>
>>> On 2/9/07, Xabier Artaechevarria Artieda <xabiarta at unav.es> wrote:
>>>>
>>>> Hallo Christoph,
>>>> Thanks for the answer.
>>>> I checked after 174 iterations and the overlap seems in fact good,
>>>
>>>
>>> How did you ascertain the fact that the overlap is good ? (I presume you
>>> checked the transform, but I don' tsee it printed in the log). There
>> must be
>>> a significant drift in teh transform from teh initial position to the
>>> position after 174 iterations to prompt this error.
>>>
>>> DId you try resampling with the transform and overlaying the images to
>> make
>>> sure that the transforms are headed in the right direction ?
>>>
>>> and
>>>> it is considerably better than at the first iteration. Do you think I
>>>> could solve the problem by using a higher number of spatial samples?
>>>> Now I am using one tenth of the total voxels.
>>>
>>>
>>> 1/10th for MI is plenty.
>>>
>>>
>>>>
>>
>>
>>
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>>
>>



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