Mark,
Hello.
Thank you for the confirmation. What I have tried so far is to load the
filter_func_data into MatLab and filter it that way with a fourth order
Butterworth filter. This does exactly what I want and much quicker than I
expected!. But since my aim is to do this on a large data set my plan is to
create two FEAT files. One for the pre-stats (motion corection. BET etc.)
than one for the stats and registration. I would then do the MatLab
filtering in between.
When I did this it created another filtered_func_data file! Thus doubling
the space this subject is occupying. I am guessing this is because of the
FILM application at the stats step. Is there some way to break my FEAT full
analysis into two steps but only to write out one filtered_func_data file?
Then I tried this with MatLab calling FEAT. And it didn't work, it would
crash FEAT! This is my problem but I have done this before and it worked so
I don't know what is going on now.
Another idea. What if I coded into avwstats++ an improved filter? I have
read through the code and it certainly looks possible. Is there any
documentation or advice that would aid me in the modification compilation of
avwstats++? Just to give me some guidance.
Thank you,
Jason.
On Tue, 28 Nov 2006 07:51:44 +0000, Mark Jenkinson <[log in to unmask]> wrote:
>Dear Jason,
>
>I'm sorry but the bandpass filtering in avwmaths++ is our only
>available temporal filtering option at the moment.
>
>You could stick with Matlab (using our i/o routines in
>$FSLDIR/etc/matlab) or modify something like avwpspec to
>output the real and imaginary parts of the fft and do
>everything via multiplication in the frequency domain
>(although you'll have to read and write separate the real
>and imaginary components, and do the maths appropriately,
>as complex data is not really supported except in
>avwcomplex and prelude).
>
>Sorry we don't have a better solution at present.
>
>All the best,
> Mark
>
>
>On 27 Nov 2006, at 13:19, Alle Meije Wink wrote:
>
>> Hmm, don't know if there's a tool for that, sorry. Maybe you want the
>>
>> avwmaths++ -bptf
>>
>> option? I have never used it myself so cannot help you with it, but
>> btpf stands for bandpass temporal filtering.
>>
>> From the help (which you get by just calling avwmaths++) it looks
>> like a sharp cutoff in frequency. That gives you a temporal
>> response which is quite smeared out.
>>
>> hth
>> Alle Meije
>>
>> Jason Steffener wrote:
>>> Hello. Thank you for the reply. I am interested in only temporal
>>> filtering.
>>> Yes the methods you describe all make sense. I do not need an
>>> "ideal" filter
>>> just an imporved one. By a higher-order (or higher-taps) filter I am
>>> refering to one that will use more time points and have the
>>> ability to
>>> provide a sharper cutoff (a smaller transition band). And it is
>>> this smaller
>>> transition band that I am most interested in. I know that I can do
>>> this in
>>> MatLab easily enough. However, I am interested in streamlining
>>> things so it
>>> would be ideal to have an improved filter in FSL.
>>> Thank you,
>>> Jason.
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