Hi - no sorry I meant that 1+6sigma is the size of the window within which the Gaussian is created. The FWHM is ~2sigma as always
Cheers
--------------------
Stephen M. Smith, Professor of Biomedical Engineering
Associate Director, Oxford University FMRIB Centre
FMRIB, JR Hospital, Headington,
Oxford. OX3 9 DU, UK
+44 (0) 1865 222726 (fax 222717)
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http://www.fmrib.ox.ac.uk/~steve
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On 11 May 2011, at 13:48, Laurence Hunt <[log in to unmask]> wrote:
> Hi all,
>
> Quick Q on -bptf filtering in fslmaths - does what you've written below imply that if I've got a TR of 25ms - MEG data, not fMRI ;-) - and want to smooth with a kernel of FWHM 250ms, I'd need
>
> fslmaths in1.nii.gz -bptf -1 1.5 out.nii.gz
>
> as FWHM = 1+6*sigma, so
> sigma = 6/(10-1) = 1.5
>
> ?
>
> Thanks,
> L
>
> On 17 Jun 2010, at 07:39, Stephen Smith wrote:
>
>> The full width of the kernel containing the filter is 1+6*sigma.
>>
>
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