Dear Robert,
> What seems silly is that realignment (also, smoothing, coregister, normalization) is a process that does NOT require all images to be in memory at once, since they are being realigned to the first common image. (Admittedly, slice timing does, but only a small handful for interpolation).
(i) if you motion correct the time-series during realignment the whole time-series needs to be processed.
(ii) in slice timing correction we chose Fourier interpolation to shift the phase and again the whole time-series needs to be in memory.
> What would seem to be actually better programming practice would be to only hold in memory the image that is being realigned (smoothed, coregistered, normalized) Or, if there is sufficient memory, a small number of images optimized disk i/o.
The mails by R. Welsh prompt me to comment on a recent change in "tone" on the SPM helpline. SPM is a research tool provided free of charge by the methods group of the Wellcome Dept of Cognitive Neurology. Although I can understand that it is annoying when SPM crashes, it is inappropriate to
ask for fixes "ASAP" and imply that the code (and author?) "seems silly". Don't forget, the authors are scientists. Their main job is research. I am using SPM for 5 years now and find it a wonderful tool and toolbox. Nobody has to use it. Be assured that the authors address questions asap,
without explicitly being asked to.
--
-Christian Buechel
--
Dr. Christian Buechel
Neurologische Universitaetsklinik, Haus B
Universitaets-Krankenhaus Eppendorf
Martinistr. 52
D-20246 Hamburg
Germany
Tel.: +49-40-42803-4726
Fax.: +49-40-42803-5086
email:[log in to unmask]
www.uke.uni-hamburg.de/kliniken/neurologie/pages/mitarbeiter/buechel_c.htm
www.uke.uni-hamburg.de/kliniken/neurologie/pages/forschung/cnl_index.htm
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