Using topographic map

About the GUI application to design signal processing pipelines
Post Reply
ariandy
Posts: 25
Joined: Fri Aug 14, 2009 3:11 am

Using topographic map

Post by ariandy »

Dear Yann Renard,

I'm sorry if this is a stupid/newbie question. I'm still wondering how to display 2D topographic map for online acquisition with 2 channels ModEEG hardware. Especially I dont' understand what kind of data should I provide to the "Channel Localization" input in 2D topographic map box. In the sample scenario, Channel Localization is given with provided electrode information. When I change the input file in GDF reader (with recorded 2 channel EEG data), topographic map doesn't display anything. Also when I change the input to acquisition client, and provide topographic map with channel localization data from the acquisition box, still it doesn't display anything.

Could you give me detail or step-by-step instruction about displaying 2D topographic map?

And one more question I want to ask, is there any option to make multi-view signal to be displayed in different color?

Thank you for your assistance.

yrenard
Site Admin
Posts: 645
Joined: Fri Sep 01, 2006 3:39 pm
Contact:

Re: Using topographic map

Post by yrenard »

ariandy,

the channel localisation tells the 2d topographic map visualisation where the electrodes are actually located on the scalp. In order to do this, the channel names from the channel localisation must be the same as the names of your signal channels. For an example, check the share/electrode_sets/electrode_set_standard_cartesian.txt file.

However, you say you use 2 channels ModEEG. But the topographic map visualisations needs more channels in order to interpolate the information on the surface of the scalp. You won't be able to display anything "looking real" with only two channels...

Tell me if you need more information.
Yann

ariandy
Posts: 25
Joined: Fri Aug 14, 2009 3:11 am

Re: Using topographic map

Post by ariandy »

yrenard wrote:ariandy,

the channel localisation tells the 2d topographic map visualisation where the electrodes are actually located on the scalp. In order to do this, the channel names from the channel localisation must be the same as the names of your signal channels. For an example, check the share/electrode_sets/electrode_set_standard_cartesian.txt file.

However, you say you use 2 channels ModEEG. But the topographic map visualisations needs more channels in order to interpolate the information on the surface of the scalp. You won't be able to display anything "looking real" with only two channels...

Tell me if you need more information.
Yann
hmm.. Okay then, so my 2 channel ModEEG isn't enough to display topographic map.

How about color differentiation in signal display's multi-view?

I'm doing research on Mu wave captured at C3 and C4 using OpenViBE without training (only using weights), and I'm having difficulties on displaying interpolated data which shows difference between left and right hand movement activity. I'm thinking about joining the averaged signal display together, but no color option makes it hard to analyze visually.

Thank you

yrenard
Site Admin
Posts: 645
Joined: Fri Sep 01, 2006 3:39 pm
Contact:

Re: Using topographic map

Post by yrenard »

ariandy wrote: hmm.. Okay then, so my 2 channel ModEEG isn't enough to display topographic map.
sure it's not.
ariandy wrote: How about color differentiation in signal display's multi-view?
Sorry I forgot to answer this one :p we do not have such functionality for now and I experienced this need recently too... I guess it won't be considered as critical in the roadmap for now but you should take a couple of minutes to fill in a feature request in the bug tracker so we do not forget this.
As a work around, I suggest you channel select the two different groups and use two different signal displays. (this is probably the best you can do for now)

Also there is no such functionality as requesting multi-view before scenario execution (e.g. in the box parameters). Please fill in a feature request in the bug tracker so we do not forget this.
ariandy wrote: I'm doing research on Mu wave captured at C3 and C4 using OpenViBE without training (only using weights), and I'm having difficulties on displaying interpolated data which shows difference between left and right hand movement activity. I'm thinking about joining the averaged signal display together, but no color option makes it hard to analyze visually.
As I said, multiple channel selector + signal display most probably is the best you can have for now. Spatial filter may help in comparing the values also. However, if you have knowledge in C++ and time for patching the code, this would be a nice contribution. You should then take a look at openvibe-plugins/simple-visualisation/trunc/src/ovpCSignalDisplay/*.*. There is an automatic coloring of the stimulations so you probably can use something similar for the signals.

Tell me if you need more assistance on this.

Best regards,
Yann

Post Reply