sdeiss at ucsd.edu
Thu Jul 12 19:01:14 CEST 2012
Thanks for this note. Changing the call in read_biosig_header and
read_biosig_data does make the problem go away, ie., the digital trigger
channel is not zeroed. I do not know what other side effects there
could be. So I am a little wary.
On 07/11/12 01:20, "Jörn M. Horschig" wrote:
> Dear Steve,
> Although I cannot help you directly and do not know about the specific
> error you got, you can find all code changes on
> For the biosig file you are referring to, please look here:
> (but as you can see, nothing changed there)
> Hope someone else can help out (Robert is on vacation right now, so
> maybe someone else can help)
> On 7/10/2012 8:49 PM, Steve Deiss wrote:
>> The fieldtrip version we have calls function 'read_biosig_header'
>> which calls 'sopen' with the following sequence.
>> biosig = sopen(filename,'r');
>> For some reason it loses the digital triggers on channel 1 in our
>> data after issuing the following warning:
>> "Reading data file header...
>> WARNING SOPEN(EDF): Physical Max/Min values of EDF data are not
>> necessarily defining the dynamic range.
>> Hence, OVERFLOWDETECTION might not work correctly. See also
>> EEG2HIST and read
>> http://dx.doi.org/10.1016/S1388-2457(99)00172-8 (A. Schlgl et al.
>> Quality Control ... Clin. Neurophysiol. 1999, Dec; 110(12): 2165 -
>> A copy is available here, too:
>> http://www.dpmi.tugraz.at/schloegl/publications/neurophys1999_2165.pdf "
>> If we let EEGLAB read the data, its function 'pop_biosig' calls
>> 'sopen' with
>> biosig = sopen(filename,'r',0,'OVERFLOWDETECTION:OFF');
>> The data read in here includes the triggers so that we can go on to
>> epoch and process the data.
>> We are not yet ready to upgrade to the very latest fieldtrip. So I
>> would like to know if there is an easy way to
>> determine if the latest version of fieldtrip changed anything in the
>> way sopen is called from read_biosig_header?
>> If it matches what EEGLAB does here, we can match that as a temporary
>> I'll try to download and unpack it to see, but if this is a known
>> problem, fixed or not, I'd appreciate any tips.
>> fieldtrip mailing list
>> fieldtrip at donders.ru.nl
Steve Deiss, M.Sc.
MMIL Lab (Dale and Halgren), UCSD, La Jolla, CA, USA
Neuroimaging Research Associate
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