Search found 23 matches

by dyd1985
17 Nov 2011, 12:33
Forum: BCI Systems - Signal Processing
Topic: ARFilter Spectral Estimation
Replies: 14
Views: 7190

Re: ARFilter Spectral Estimation

thank you Alessandro!! the problem is that i control the value during the online operation and they differ a lot from the values obteined during the offline analysis. I think that the only parameters that could be different is "NumericWindow" because i don't understand where is setted in the matlab...
by dyd1985
17 Nov 2011, 10:52
Forum: BCI Systems - Signal Processing
Topic: ARFilter Spectral Estimation
Replies: 14
Views: 7190

Re: ARFilter Spectral Estimation

Hi, i have the opposite problem. during online analysis, i want to obtain with the ARFilter the same spectra as that in the offline analysis. It's too important for me because i want to determine a threshold value looking the spectra plot and the r^2 plot obteined in the offline analysis and use it...
by dyd1985
17 Jun 2011, 14:31
Forum: BCI Systems - Signal Processing
Topic: ARFilter Spectral Estimation
Replies: 14
Views: 7190

Re: ARFilter Spectral Estimation

Thanks, I appreciated it. I'm sorry but still I can't get it. Let me try with an example. I have attached a snapshot of AR filter parameters' configuration. Let's assume that I want to use the same configuration in Matlab when calling the mem function. Would my parameters be: sampfreq = 512; ModelOr...
by dyd1985
14 Jun 2011, 12:29
Forum: BCI Systems - Signal Processing
Topic: ARFilter Spectral Estimation
Replies: 14
Views: 7190

Re:

Hi, for offline simulations, BCI2000 comes with two tools which might be interesting to you: A) Command line processing ( http://www.bci2000.org/wiki/index.php/User_Reference:Command_Line_Processing ) allows you to apply BCI2000 filters to offline data, interrupt the processing at any point, and st...
by dyd1985
14 Jun 2011, 11:59
Forum: BCI Systems - Signal Processing
Topic: Multiple Channels (EEG & Galvanic Skin Response)
Replies: 2
Views: 2769

Re: Multiple Channels (EEG & Galvanic Skin Response)

I'm definitely not an expert, but I think you should be able to do it. You just need to set the Transmission Filter in order to transmit only the channels that you are interested in processing online. In the SOURCE menu, scroll down to the bottom and you will find TransmitChList. The GSR channels wi...
by dyd1985
14 Jun 2011, 11:01
Forum: BCI Systems - Signal Processing
Topic: Trouble using mem() function in MATLAB
Replies: 2
Views: 2391

Re: Trouble using mem() function in MATLAB

Hey Gerv,

as always thank you so much. I tested and you were right, LastBinCenter and BinWidth must be specified in Hz and not as normalized frequency.

Thanks,
Alessandro
by dyd1985
13 Jun 2011, 16:55
Forum: BCI Systems - Signal Processing
Topic: Trouble using mem() function in MATLAB
Replies: 2
Views: 2391

Trouble using mem() function in MATLAB

Hi, I'm trying to use the mem() function in MATLAB with EEG signals imported using load_bcidat('..','-calibrated'), but the plots I get are very weird, the spectral power decreases exponentially. So in order to test the MEM function I'm trying to use some sinusoidal inputs plus white noise (because ...
by dyd1985
08 Jun 2011, 12:11
Forum: BCI Systems - Signal Processing
Topic: Command line processing and matlab
Replies: 6
Views: 3769

Re: Command line processing and matlab

Hi Alessandro, I cannot find a significant difference between files loaded by load_bcidat vs load_bcimat. This is what I did: First I executed on the command line: bci_dat2stream < yuriS001R07.dat | TransmissionFilter | bci_stream2mat > yuriS001R07.mat Then, in Matlab: >> m = load_bcimat( 'yuriS001...
by dyd1985
08 Jun 2011, 10:45
Forum: BCI Systems - Signal Processing
Topic: Command line processing and matlab
Replies: 6
Views: 3769

Re: Command line processing and matlab

mellinger wrote:Dear Alessandro,

could you send me the data file in question, so I can try myself?

Best regards,
Juergen

Sure.
I have attached the acquisition run I have used.

Thank you so much for your help.
Alessandro
by dyd1985
08 Jun 2011, 09:59
Forum: BCI Systems - Signal Processing
Topic: Command line processing and matlab
Replies: 6
Views: 3769

Re: Command line processing and matlab

Dear Juergen, thank you so much for your reply. I imported in Matlab the signals as calibrated, in both cases. Default for load_bcimat() and '-calibrated' mode for load_bcidat(). Moreover I have made sure that SourceChOffset is set to zero and SourceChGain (that gives calibrated units) is non-zero. ...
by dyd1985
07 Jun 2011, 11:06
Forum: BCI Systems - Signal Processing
Topic: Command line processing and matlab
Replies: 6
Views: 3769

Command line processing and matlab

Hey everyone, I have a new issue. I'm working offline using the command line processing and importing then the results in matlab. But when I compare my data imported in matlab using the load_bcidat() function to the data generated by the command line " bci_dat2stream < mydata.dat | TransmissionFilte...
by dyd1985
31 May 2011, 09:51
Forum: BCI Systems - Signal Processing
Topic: Help with data analysis
Replies: 2
Views: 2218

Re: Help with data analysis

Hello Dr. Schalk, Thank you so much for your reply. Hi, It seems as if the data are actually quite reasonable. R^2 of 0.2 with peaks at C3 and C4. I would do topographies in addition to the spectra, but you should see nice typical peaks over motor cortex. There is considerable inter-subject variatio...
by dyd1985
27 May 2011, 13:00
Forum: BCI Systems - Signal Processing
Topic: Help with data analysis
Replies: 2
Views: 2218

Help with data analysis

Hi everybody. I have a question... I already know that is almost impossible for you to give me accurate answers, considering you don't know much on my data acquisition system... anyway, I have attached the results of the offline analysis of recently acquired data. It was a long training session with...
by dyd1985
21 Mar 2011, 12:02
Forum: BCI Systems - Brain Signals
Topic: What's the best reference location to use?
Replies: 1
Views: 2569

What's the best reference location to use?

Hello,

I was wondering what the best location for the reference electrode is. I found some works where the authors used mastoids... what about earlobes? Can you please suggest some papers to support an eventual choice.

Thanks
Alessandro
by dyd1985
23 Aug 2010, 16:28
Forum: Software Development
Topic: NIDAQ_mx source module development
Replies: 2
Views: 1692

Problem Solved

Hi, after some time spent debugging the code I realized that all my problems were related to data type conversion issues. Specifically, my A/D board digital output is a 16 bit unsigned integer and so all the acquisition part of the code must manage my data as unsigned integer. Then I converted this ...