One version takes into accout the voxel sizes etc, whereas the other doesn't.
The displayed one is a mapping from mm in one image, to mm in another,
whereas the one in the sn.mat file is from voxels in one file to voxels in
the other.
Best regards,
-John
On Tuesday 26 July 2005 09:44, Jürgen Hänggi wrote:
> Dear SPM users
>
> this qustion is related to the email with the title
> "Confusion about segment volume".
>
> Although the matrix from affine registration looks well
> in the graphic window of spm2 after normalisation
> e.g.
> X1 = 1.040*X + 0.017*Y + 0.002*Z - 2.018
> Y1 = -0.002*X + 1.038*Y - 0.021*Z + 5.779
> Z1 = -0.011*X - 0.028*Y + 1.234*Z - 0.272
>
> but when I open the file *.sn.mat in the MATLAB workspace and then the file
> affine the same matrix looks like
> e.g.
> -0.984652397319312 -0.01601706430295645 -0.002118768348360404
> 201.0153957960537
> 0.009009810452331476 -0.40483913770032703 -0.7711390007527495
> 192.507048140182
> -9.784690721137174E-4 -0.48843170079109083 0.16698600269962102
> 100.13643261690986
> 0.0 0.0 0.0
> 1.0
>
> As you can see the parameters in the matrix have changed from the graphic
> window to the affine file and the calculated determinant looks very
> strange!
>
> Where is the problem?
>
> Thanks a lot for helpimg in advance
> best regards
> Juergen
>
> ----------------------------------------------
> Juergen Haenggi, Ph.D. student
> Division of Psychiatry Research
> Psychiatric University Hospital
> University of Zurich, Switzerland
> P.O. Box 1931
> Lenggstrasse 31, 8032 Zurich
> 0041 44 384 26 10 (office phone)
> 0041 76 445 86 84 (mobile phone)
> 0041 44 384 26 86 (fax)
> H 115 (office room number)
> [log in to unmask] (division email)
> http://www.dpr.unizh.ch/ (division website)
> http://www.juergenhaenggi.ch (private website)
> ----------------------------------------------
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