The first part of spatial normalisation via the Segment button can sometimes
go wrong. This is an affine registration with tissue probability maps of GM,
WM and CSF. The main reason for the occasional failure is that the
registration does not make any use of non-brain tissue probability maps,
which makes the procedure less robust.
If you can approximately align your images prior to running Segment, then
this will increase the robustness. Another thing that may help would be to
change the regularisation of the initial affine registration, via
Segment->Custom->Affine Regularisation. If you set this to "ICBM space
template - East Asian brains", then the algorithm will make use of knowledge
about the approximate variability to expect among the width/length etc of the
brains of the population.
Best regards,
-John
On Sunday 16 September 2007 13:21, 申林 wrote:
> hi, SPMer,
> there are something wrong with my normalized images. i followed the
> SPM5 manual recommend pre-procession procedure and display normalized
> images found that anterior part of frontal lobe is out of display but
> those unnormalized images are correct position in display window. what i
> want to know are :
> 1) what cause the unexpected images ?
> 2) how to resolve the problem?
>
> i try to resolve the problem by running twice normalize .
> first one with estimate and write , template : data->mean function image
> ; template image->EPI (SPM5 template) second one with write , parameter
> file-> .mat file maked from the first normalize.
>
> the method locate normalized images in right position but larger than prior
> unexpected image.
>
> 3) is the method of twice normalize proper? why size of twice
> normalized image is larger than that of one normalized image?
>
> thank you in advance for pointer and suggestion!
>
> lin shen
> 2007.9.16
>
>
> Lin Shen, MMS, Department of Neurology,
> The First Affiliated Hospital, ChongQing Medical University
> No.1, Yixueyuan Road, ChongQing 400016, China
> Phone: +86 23 13193076520
> E-mail: [log in to unmask]
>
>
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