AFNI Message Board

Dear AFNI users-

We are very pleased to announce that the new AFNI Message Board framework is up! Please join us at:

https://discuss.afni.nimh.nih.gov

Existing user accounts have been migrated, so returning users can login by requesting a password reset. New users can create accounts, as well, through a standard account creation process. Please note that these setup emails might initially go to spam folders (esp. for NIH users!), so please check those locations in the beginning.

The current Message Board discussion threads have been migrated to the new framework. The current Message Board will remain visible, but read-only, for a little while.

Sincerely, AFNI HQ

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Zhihao_Li
September 26, 2014 10:02AM
Hi AFNI experts,
When performing a "orig->tlrc" transformation on EPI data, I noticed that "@auto_tlrc" would reduce the spatial smoothness in the newly generated "tlrc" data while "adwarp" would not. Could you please explain me why?
Here is what I did:

3dFWHMx -mask epi_mask+orig epi+orig
++ 3dFWHMx: AFNI version=AFNI_2011_12_21_1014 (Apr 11 2014) [64-bit]
++ Authored by: The Bob
++ Number of voxels in mask = 23778
7.22925 6.22382 4.82046

3dcalc -prefix epi_for_adwarp -a epi+orig -expr 'a';
adwarp -apar anat+tlrc -dpar epi_for_adwarp+orig;
3dFWHMx -mask anat+tlrc epi_for_adwarp+tlrc
++ 3dFWHMx: AFNI version=AFNI_2011_12_21_1014 (Apr 11 2014) [64-bit]
++ Authored by: The Bob
++ Number of voxels in mask = 1948925
7.47012 6.19473 5.89288

3dcalc -prefix epi_for_autotlrc -a epi+orig -expr 'a';
@auto_tlrc -apar anat+tlrc -input epi_for_autotlrc+org;
3dFWHx -mask anat+tlrc epi_for_autotlrc+tlrc
++ 3dFWHMx: AFNI version=AFNI_2011_12_21_1014 (Apr 11 2014) [64-bit]
++ Authored by: The Bob
++ Number of voxels in mask = 1948925
5.80593 4.92356 4.93437
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Subject Author Posted

why "@auto_tlrc" reduce spatial smoothness?

Zhihao_Li September 26, 2014 10:02AM

Re: why "@auto_tlrc" reduce spatial smoothness?

Peter Molfese September 26, 2014 10:48AM

Re: why "@auto_tlrc" reduce spatial smoothness?

Zhihao_Li September 26, 2014 11:02AM