[FieldTrip] weight table for 4D data
jan.schoffelen at donders.ru.nl
Wed Jul 20 16:06:00 CEST 2011
I did not suggest to use the 4D software.
I pointed to some documentation which probably was not clear enough.
You can look at the hdr.grad.tra matrix (after reading in the header using fieldtrip, and specifying the raw data file, so no .m4d or .xyz nonsense here).
if you do:
figure;imagesc(hdr.grad.tra), you'll see a matrix which essentially has the colourful bits at the far right side of it. These correspond to the weights. If you have a gradiometer system, this probably corresponds to hdr.grad.tra(1:248,597:end), for a magnetometer system it will be hdr.grad.tra(1:248,249:end). The lower right part of the tra matrix hdr.grad.tra(249:end, 249 (or 597):end) allows you to decode which reference coils contribute to which reference channel.
On Jul 20, 2011, at 3:01 PM, Luo, Jessie (NIH/NIMH) [V] wrote:
> Thank you Jan-Mathijs and Yuval for replying!
> Unfortunately I don't have the 4D software.
> Do you happen to know what specific commands in fieldtrip allow me to pull out the weight table?
> Many thanks,
> From: Yuval Harpaz [yuvharpaz at gmail.com]
> Sent: Wednesday, July 20, 2011 5:22 AM
> To: Email discussion list for the FieldTrip project
> Subject: Re: [FieldTrip] weight table for 4D data
> with 4D software you can write in a terminal print_table <options>. I use :
> print_table -posted -WP both > wts.txt
> this prints both analog and digital as one set of weights
> On 20 July 2011 09:29, jan-mathijs schoffelen <jan.schoffelen at donders.ru.nl<mailto:jan.schoffelen at donders.ru.nl>> wrote:
> Hi Jessie,
> Please have a look here:
> Best wishes,
> On Jul 19, 2011, at 11:08 PM, Luo, Jessie (NIH/NIMH) [V] wrote:
>> Does anyone know where the weight table for 4D datasets (from 248 channel 4D machine) is stored and how to extract it from the dataset?
>> Many thanks!
>> fieldtrip mailing list
>> fieldtrip at donders.ru.nl<mailto:fieldtrip at donders.ru.nl>
> Dr. J.M. (Jan-Mathijs) Schoffelen
> Donders Institute for Brain, Cognition and Behaviour,
> Centre for Cognitive Neuroimaging,
> Radboud University Nijmegen, The Netherlands
> J.Schoffelen at donders.ru.nl<mailto:J.Schoffelen at donders.ru.nl>
> Telephone: +31-24-3614793
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> fieldtrip at donders.ru.nl<mailto:fieldtrip at donders.ru.nl>
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Dr. J.M. (Jan-Mathijs) Schoffelen
Donders Institute for Brain, Cognition and Behaviour,
Centre for Cognitive Neuroimaging,
Radboud University Nijmegen, The Netherlands
J.Schoffelen at donders.ru.nl
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