OpenViBE forum

We are trying to replace the arrow and the crossbar that appears in the Graz Motor Imagery BCI Simulator (provided in /openvibe/share/openvibe-scenarios/bci/motor-imagery/motor-imagery-bci-0-signal-monitoring.xml) with alternate stimulus.

How can we replace the arrow and the crossbar that appears during the trials with an alternate stimulus, for instance an image that appears at the center of the screen indicating the intent to the user, or multiple images?

We tried replacing the stimulation codes in the class 1 and class 2 fields of the configure box dialog of the Simulator, but only the arrow does not appear when the simulation is run.

Dear sumitsoman,

thank you for reposting publicly as advised, this will be helpful for other readers.

On one hand, the Graz visualization box is not (very) flexible (at all). If you want to modify its behaviour, you will have to get into the C++ code and hack from there so that it matches your needs. Depending on your programming skills and your comfort with C++ and GTK, this might be easy or not.

On the other hand, there are boxes that you could use to meet your objectives. My bet is that the Display Cue Image should be able to display a picture for each of the { instruction | feedback } you need. I anticipate that you will have several stimulations streams with different labels and that you will have to merge them in a single stream using the Lua Stimulator. Then each stimulation would lit up the { instruction | feedback } accordingly.

If you feel comfortable with Lua, you may also look at Lua Window, a Lua extension that will enable the handling of pictures/text in a single window depending on a Lua script you write inside OpenViBE.

I hope this helps,
Have fun with OpenViBE,
Yann

Can anyone recommend an example using Lua Window or display cue, etc? I have the exact same objective as this OP did 5 years ago.

Incidentally, what does the word "Graz" mean? I'm just curious. None of the definitions I found online made sense in this context.

Hi Hackr,

you can look into the ERP Recording Tutorial to see how Cue Display is used to show different images depending on the events in an experiment timeline. The Cue Display box doesn't show feedback (unlike Graz Display box) but its easier to use it to show a lot of different images (arrows, crosses, whatever, ...). The role of the Lua script in that is just to generate what events are supposed to happen and when.

To explain the lore a little, that particular motor imagery paradigm originated from the Technical University of Graz, Austria. The institute still exists! If you're interested there is a BCI conference there right this month.

https://www.tugraz.at/institute/ine/gra ... ence-2017/

Hope this helps,
Jussi

jtlindgren wrote:Hi Hackr,

you can look into the ERP Recording Tutorial to see how Cue Display is used to show different images depending on the events in an experiment timeline. The Cue Display box doesn't show feedback (unlike Graz Display box) but its easier to use it to show a lot of different images (arrows, crosses, whatever, ...). The role of the Lua script in that is just to generate what events are supposed to happen and when.

To explain the lore a little, that particular motor imagery paradigm originated from the Technical University of Graz, Austria. The institute still exists! If you're interested there is a BCI conference there right this month.

https://www.tugraz.at/institute/ine/gra ... ence-2017/

Hope this helps,
Jussi

Awesome, thank you! Incidentally, I have been enjoying several of your old slideshows I found on this site.