Dear SPMers
I’ve been trying to normalize SPGR T1W images (256x256x106
0.94mmx0.94mmx1.50mm) using SPM5 VBM segmentation function
(native+modulated+unmodulated). I use matlab 7.1 in Linux with the update
456.
I wanted to compare the differences between “with” and “without” non-linear
transformation, so I turned on non-linear transformation by setting DCT
cutoff=25 and turn it off by setting it to DCT cutoff=inf. All of other
parameters are set to the default values. I was expecting affine
component, which was extracted from ”_seg_sn.mat”, to be the same between
the two ways, but they turn out to be different.
I appreciate if anyone has an explanation for this.
”_seg_sn.mat”
DCT cutoff=25
2.1310 -0.0608 0.0777 28.1888
0.0796 2.0519 -0.5784 15.4785
-0.0364 0.3629 1.2825 -13.4118
0 0 0 1.000
DCT cutoff=inf
2.1315 -0.0478 0.0745 27.6491
0.0660 2.0546 -0.5704 15.9588
-0.0369 0.3577 1.2839 -12.8985
0 0 0 1.000
Thanks,
Hedok Lee
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