Recreate Region Based Speller

Working with OpenViBE signal processing scenarios and doing scenario/BCI design
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User
Posts: 16
Joined: Wed May 18, 2016 8:43 pm

Recreate Region Based Speller

Post by User »

Hi everyone,

I'm trying to simulate the Region Based speller (RB) in (http://ieeexplore.ieee.org/xpl/login.js ... %3D5443854) using OpenViBE.

My initial thoughts are to change the 6x6 matrix found in P300 speller to a 3x5 matrix (rows x columns) and create another level of the letter selection with another matrix of the same size. Since the RB speller first have to select a region that contains 7 characters (first level) and then move on to the next level where we can select the target character among others that belong to the same region.

The flashing sequence, it would be random not in a row/column way rather in P300 magic card.

I'm trying to do that using P300 speller xDAWN -although from what I read that CoAdapt is more suitable to my requirements unfortunately I couldn't get it to install-.

My questions here are:

0- What do you think is more better, to start with P300 speller xDAWN and change it to the RB speller or to start with the P300 magic card and turn it into RB speller?

0.1- if P300 speller is better, how can I make the flashing sequence random?

1- How can I create the two stages of the speller? such that The target region will be selected then it would be intensified to select the target letter?

2- How can I change the matrix size from its default size to to 3x5 -3 rows x 5 cols-?

3- Is it possible to select say 7 cells to flash randomly and ignore the rest since the rest 8 will be empty? and if yes, how?

4- Finally, if I finished this speller how can I test it in copy mode? such that if the user fail to select the region that contains the target letter in the first level, region x, it would be counted as an error, and the speller will intensify region x.

Your help is deeply appreciated.

nfoy
Posts: 40
Joined: Fri Nov 14, 2014 1:06 pm

Re: Recreate Region Based Speller

Post by nfoy »

Hi

I believe that the P300 speller xDawn is a good start to implement the behavior you want.

You can for instance create a Lua script to implement any flashing strategy and connect it to the P300 Visualisation box.

The configuration file p300-speller-visualisation.cfg will allow you to modify the dimensions of the grid.

In order to have the two-level flashing strategy, you need to have a feedback from the P300 accumulator, that you can connect to the box running the Lua script where you implemented your flashing strategy.

Happy hacking

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