Dear Alois,
> We aquired a block of only 15 slices which does not
> contain the anterior commissure, which is situated a
> little bit caudal from the most inferior slice of the
> block. So it is not possible to set the origin
> properly.
> After normalisation the images are rotated or
> dislocated.
> Is there any possibility to compensate this problem?
SPM's normalisation process is very sensitive to starting
transformations. To converge to the right result, the images should not
differ a lot (this is referred to as the 'capture range' of the
normalisation algorithm'). When the image you want to normalise differs
much from your template image, you might want to give spm_sn3d a push by
setting a starting transformation that is already a good estimate of the
final result. The fine-tuning will be done by spm_sn3d.
If all your images need a starting estimate, you can of course automate
the whole thing...
Hope this helps,
Alle Meije
--
Alle Meije Wink
Institute for Mathematics and Computing Science, room 105
University of Groningen P.O. Box 800
9700 AV Groningen
Telephone +31 50 363 71 27 The Netherlands
Fax: +31 20 875 48 00
E-mail: [log in to unmask]
WWW: http://www.cs.rug.nl/~wink
" I guess it comes down to a simple choice, really.
Get busy living, or get busy dying. "
(Andy Dufresne in The Shawshank Redemption)
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