Search found 51 matches

by Yueqing Li
01 Feb 2010, 18:05
Forum: BCI Systems - User Applications
Topic: control signal in curosr movement application
Replies: 3
Views: 2258

Hello: Thank you very much, Adam. I have another question. If I use two control signals for the two cursor movement, for example, up and down. How could the system know which control signal is for which cursor movement? I can't find any specification of the relation between them in the BCI2000 param...
by Yueqing Li
01 Feb 2010, 16:48
Forum: BCI Systems - User Applications
Topic: cursor movement application
Replies: 7
Views: 3700

The CursorTask application is a 3D application. The cursor will move in the 3 dimensions based on the output channel of the linear classifier (see http://www.bci2000.org/wiki/index.php/User_Reference:LinearClassifier ), which is the third column of the linear classifier matrix. Therefore, to make a...
by Yueqing Li
28 Jan 2010, 16:16
Forum: BCI Systems - User Applications
Topic: cursor movement application
Replies: 7
Views: 3700

Thank you very much, Adam. It really helps. I have another question of the cursor movement application. For example, if the motor imagery of right hand movement is the control signal moving the cursor up, what exactly controls the speed of cursor's moving up? Is that the amplitude of the correspondi...
by Yueqing Li
21 Jan 2010, 16:51
Forum: BCI Systems - User Applications
Topic: control signal in curosr movement application
Replies: 3
Views: 2258

control signal in curosr movement application

Hello: I have a question about the cursor movement application in BCI2000. The tutorial said users could use the motor imagery to move the cursor up, while use relaxation to move it down. I am wondering whether they can use two different motor imageries to move the cursor up and down, respectively? ...
by Yueqing Li
21 Jan 2010, 15:27
Forum: BCI Systems - User Applications
Topic: cursor movement application
Replies: 7
Views: 3700

cursor movement application

Hi,

Does BCI2000 have 2D cursor movement application? I can only find the 1D cursor movement? Thanks a lot.
by Yueqing Li
17 Dec 2009, 12:34
Forum: BCI Systems - User Applications
Topic: channel selection in Mu rhythm
Replies: 3
Views: 2299

Hi, Adam:

Thank you very much for your quick answer.

I made a typo there. I mean right hand movement. :lol:

I think you are right. I may put the cap too far back. I will try another time.

Thanks again and have a good day.
by Yueqing Li
16 Dec 2009, 18:28
Forum: BCI Systems - User Applications
Topic: channel selection in Mu rhythm
Replies: 3
Views: 2299

channel selection in Mu rhythm

Hello: I am training users to use Mu rhythm with BCI2000. I found several questions: 1. I am trying to use left hand movement as a control signal in the curse movement. According to the tutorial, electrode C3 should be used. But, I found a bigger r square value in electrode F3 . So, should I use F3 ...
by Yueqing Li
20 Nov 2009, 11:46
Forum: BCI Systems - User Applications
Topic: Mu rhythm training
Replies: 1
Views: 1729

Mu rhythm training

Hello:

I am using Mu rhythm and follow exactly the tutorial, but found it not easy to train the users to imagine the movement. I want to know how much training is needed generally? Thanks a lot.
by Yueqing Li
03 Mar 2009, 23:44
Forum: BCI Systems - User Applications
Topic: about P300GUI
Replies: 3
Views: 2054

Dr. Schalk: Thanks for your reply. I used 10 characters in each run. So, there were totally 50 characters in the training session. Is that enough for participant with motor disabilities? I have one question for testing the training classifier weight. What is a good classifier? It seems that the accu...
by Yueqing Li
03 Mar 2009, 00:57
Forum: BCI Systems - User Applications
Topic: about P300GUI
Replies: 3
Views: 2054

about P300GUI

Hi, I met some problems in building the classifier with P300GUI. I had 5 runs in the training session. I wanted to use four of them to build the classifier and the left to test the classifier. However, I can't build a good classifier with the training data. The accuracy is always very low in the tes...
by Yueqing Li
15 Feb 2009, 01:30
Forum: BCI Systems - Signal Processing
Topic: source derivation
Replies: 3
Views: 2538

reference and ground

Hi, Dr. Schalk: Thank you for your reply. I have another two questions. 1. Since the measurement is unipolar, so I think the potential measured is in fact the difference between each electrode and the reference electrode. Is this the amplitude we use in the data analysis or just the amplifier input?...
by Yueqing Li
13 Feb 2009, 01:31
Forum: BCI Systems - Signal Processing
Topic: source derivation
Replies: 3
Views: 2538

source derivation

Hi: I have several simple questions about the source derivation. 1. What is the function of the Ground and Reference electrode on the EEG cap? Are they used to get the amplitude (or potential) for the other electrodes? 2. I know they are several ways to get the amplitude, such as CAR, etc. What meth...
by Yueqing Li
28 Jan 2009, 15:21
Forum: BCI Systems - Signal Processing
Topic: P300 GUI
Replies: 14
Views: 5449

Dr. Schalk: I have updated the BCI2000 to Rev. 2234 (I think it is the most recent version) and tried the P300GUI with it. But the same problem still existed. I wanted to use "Backspace" in the P300 Speller copy mode, but found that users could not use "Backspace" for the last target character. When...
by Yueqing Li
27 Jan 2009, 21:22
Forum: BCI Systems - Signal Processing
Topic: P300 GUI
Replies: 14
Views: 5449

Dr. Schalk: Thank you for your answer. Do you mean that it is because of the BCI2000, rather than P300GUI? Since this is part of an old experiment, to keep the consistency, I used BCI2000 V1.4 (all the training sessions have been done with BCI200 V1.4), instead of the BCI2000 V2.0. Is there any way ...
by Yueqing Li
27 Jan 2009, 18:35
Forum: BCI Systems - Signal Processing
Topic: P300 GUI
Replies: 14
Views: 5449

P300 GUI

Hi, I met some problems when using P300 GUI. I tried to use P300 GUI to produce r square plots, but got the following error message: >> P300_GUI Loading files... run 1... Collecting Responses... ??? Index exceeds matrix dimensions. Error in ==> GetP3Responses at 24 Responses.Responses(kk,:,:)=signal...