The Introduction of Designing a Hybrid Brain Computer Interface System

Abstract

Background: Brain Computer Interface (BCI) is a communication system between human brain and a computer or a peripheral device which by recording brain signals directly would send messages and commands from the human brain to computer. According to brain activity patterns of EEG, BCIs are divided into different types. The most important of these patterns called ERP (Event Related Potentials) which appears after particular events in the EEG signal. Combining various types of BCI systems is called hybrid BCI and increases the efficiency of BCI system. Materials and Methods: In this project, our concentration is on a hybrid P300-SSVEP Speller BCI system in order to enhance the accuracy. The aim of this project is to design a BCI system based on P300 and SSVEP patterns, which sequentially can be able to rectify the weakness points of the conventional BCIs. Results: Our hybrid BCI system consists of two sections including SSVEP condition and P300 condition. First, we have only six frequencies in a 6×6 speller matrix that we should detect one-group characters with same frequencies through six groups. Second, we must detect desired character that there is in selected group in previous section through 36 characters. We used two different types of software to design our hybrid BCI and we achieved a relatively high classification accuracy with our hybrid system. In order to develop a practical daily use EEG system, signals were captured with a standard low cost EMOTIV-Epoc system. Conclusion: we designed a hybrid SSVEP-P300 BCI platform by two different software. Our hybrid BCI system consists of two sections including SSVEP condition and P300 condition. In first section, as respect we had only six frequencies in a 6×6 speller matrix, we should detect one-group characters with the same frequencies through six groups. In second section, we must detect desired character that there is in selected group in previous section. This hybrid system can help to SSVEP condition to choose more commands using P300 condition so that it can help to increase the number of commands from 6 to 36 commands. In our system, we can achieve only six choices by SSVEP condition.