P300 Based Online BCI System

Brain computer interface (BCI) builds additional bridge between brain and the environment, and acts as a new interactive way. With BCIs, patients such like amyotrophic lateral sclerosis (ALS) can contact with others and finish some simple task individually.As one component of electroencephalography (EEG) signal, P300 potential is a positive peak at about 300 ms after the target stimulus onset in the EEG, occurring in response to infrequent or particularly significant stimuli. After detection with the P300 potential, we obtain some signal patterns for different tasks, by which the subject can control the computer or even other equipment.Same as the traditional interactive ways (ex. mouse, keyboard), BCI is also one kind of human computer interaction method. Nowadays, we have built an online BCI system, by which we could achieve various applications. The applications built on this system include Chinese virtual keyboard, P300 messenger, mind painting, virtual hand control and mechanical equipment control.The system consists of 3 main modules: user interface, data processing module and experiment monitor module. User interface displays both the stimulus and feedback signal to subject; Data processing module extracts features from original EEG data and converts recognized patterns into commands; Experiment monitor module helps operator to better control the system and gets more information. All the modules are connected by Socket and the system supports distributed experiment control procedure.