Hi,
On 11 Mar 2009, at 14:48, Ning Liu wrote:
> Hi Steve,
>
> Thank you for kind reply. Here are my questions:
>
> 1. Is this -ms <num> in mm? such as 5 means FWHM = 5 mm?
Yes
> 2. Shall I set the same size as I did in pre-stats spatial smoothing?
There's no reason why this would be the same - we use 5mm which is
empirically/biologically determined to be reasonable but it's not set
in stone.
> 3. in Program susan, if I want spatial smoothing FWHM is 2.0 mm, the
> option
> -dt is 0.8492569. How does it caculate?
This is the conversion from FWHM to the sigma in the Gaussian - if you
write down a Gaussian and use this sigma and then calculate FWHM,
that's what you get.
Cheers.
>
>
>
> Thanks,
>
>
>
> Ning
>
---------------------------------------------------------------------------
Stephen M. Smith, Professor of Biomedical Engineering
Associate Director, Oxford University FMRIB Centre
FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
+44 (0) 1865 222726 (fax 222717)
[log in to unmask] http://www.fmrib.ox.ac.uk/~steve
---------------------------------------------------------------------------
|