Platform Development of Online Brain-Computer Interface Competition
Constructed a brain-computer interface competition platform based on steady state visual evoked potentials (SSVEP), which consists of four parts:
(1) A stimulator program displaying numbers 0-9, BACK and CALL which flickered in different frequencies or phases;
(2) A server program receiving the EEG signal from the amplifier and sending it to the client programs;
(3) Client programs using candidates' codes to process the EEG signal, get the SSVEP features and send the classification results to the display program;
(4) A display program showing the results of four teams at the same time and grading them by the accuracy and efficiency
Via the system, a subject was capable of dialling merely by eye focusing, and several teams were able to compete in judging what telephone number the subject had dialled.
Principle of SSVEP
SSVEP are signals that are natural responses to visual stimulation at specific frequencies. When the retina is excited by a visual stimulus ranging from 3.5 Hz to 75 Hz, the brain generates electrical activity at the same (or multiples of) frequency of the visual stimulus.
Design of the stimulator
The stimulator program displaying numbers 0-9, BACK and CALL flickering in different frequencies or phases, which evoke different SSVEPs in the subjects' EEG signals.
Competition Area Arrangement
Display program GUI
The display program shows the results from four teams at the same time and grading them by the accuracy and efficiency.