Help with motor imagery

[chantrip]

Dear all

I'm using Emotiv headset and working on the motor imagery scenario. I started from motor-imagery-0 file to monitor the signal status, then with motor-imagery-1 file to collect some training data. However, when I tried motor-imagery-2 to train the LDA classifier using the data obtained when running motor-imagery-1 file, the log said '0 channels selected' as shown in the attached file. I believe this has to do with

The <u>preprocessing</u> of this scenario consists
in re-referencing all the channels to the
channel 2 (which was located on the nose) and
to select the 10 channels over the motor cortex
of the hands. The <i>Spatial Filter</i> box computes
a surface laplacian filter and reduces the output
to two channels: one on the left and one on the right.

Could you please tell me how to configure the channels to work with Emotiv headset?

Thank you very much

-Jim

[lbonnet]

Hi Jim !

Could you please tell me how to configure the channels to work with Emotiv headset?

As you pointed out these scenarios are using a Reference Channel. The reason is simple: the device we used (MindMedia NeXuS32b) did not have a common reference and we chose to take one of the channels as a reference. This reduces the noise.
Afterward a spatial filter is computed (Surface Laplacian on the right and left motor cortices).

When using the Emotiv headset, you definitely have to change the scenarios.
1. you don't need a reference channel box, as the headset already ave its own reference system.
2. you can't achieve the surface laplacian given the EPOC electrode placement.

If you didn't do it already, please consider updating your openvibe installation to the latest version (tag 0.11.0 or latest SVN).
I added a set of scenarios for motor imagery of the hand using spatial filter computed with CSP.
This will automatically compute the 'best' spatial filter that discriminates the 2 classes Right and Left.

CSP will cost you one more step in the process :
0. monitor the signal
1. acquire a session
2. Train the CSP
3. Train the classifier
4. Online session
(5.) replay the data and check the performances

Come back to us if you experience any problem with these scenarios, we will do our best to help.

Laurent-

[chantrip]

Hi Laurent

Thank you very much for your information. I downloaded and installed openvibe-0.11.0 in my windows XP machine. How to connect my Emotiv headset with the Acquisition server since I don't see EPOC emotive in the list of the driver?

Thank you

-Jim

[lbonnet]

Hi Jim,

If you downloaded and installed the windows binary (i.e. the windows installer) you won't have the Emotiv driver.
We are not allowed to redistribute within the installer the Emotiv DLLs.

You have to download the sources (from latest SVN or zip archive) and build the software, as you already did if you had a valid emotiv driver before.

Laurent