The Research Of Several Trials Extract P300in Event-related Potential Based On WICA

An event-related potential (ERP) is a series of brain waves which with fixed time relationship to actual or expect stimulus(voice、light、 electricity etc.). And P300is the important component of ERP, it is closely related to cognitive function such as attention identification、decision-making、memory etc. However, it is hard to extract P300in Event-related potential from EEG signals, because ERP is so tiny and be submerged in EEG signals, at the same time it is easy to be disturbed by environmental noise. we usually extract P300with40～100superposed average, Therefore, how to extract P300from original signals with less superpositions has to be an important and difficult problem.ERP is submerged in EEG signals. In recent years, Independent Component Analysis(ICA) is widespread used in the signal processing field as a new Blind Source Separation method, it can isolate the independent signals from the multichannel observation data and can’t be restricted by mess superposition, so it is suitable to remove noise in brain signals. Wavelet Transform with the well ability of time-frequency analytical and increasingly mature theory, it has been applied to brain electrical signal, and gradually both of the two methods are combined to process biomedicine signals to make up each other’s shortage.This paper combined ICA with Wavelet Transform to extract P300in Event-related potential. The main work is as fllows:(1) Introduces the emerge principles、characters、classify and use of the EEG、 ERP and P300.(2) Studying the arithmetics of ICA and Wavelet Transform in detail, processing EEG signal with WICA. First, EEG de-noise with db5, then decompose them into independent components, choise the independent components accroading to the priori knowledge of ERP, last, reconfigurate the independent components to obtain the new EEG signals.(3) Do several overlying with fixed time relationship to obtain the ERP, extract sub-components of the compound wave P300according to the priori knowledge of P300. These sub-components have significant meaning for us to research human’s higher nervous activity.(4) The comparison of test, compare the P300extracted by WICA with which exteacted by troditional medthod, it shows that the P300extracted by WICA nearly has the same characters as the P300exteacted by troditional medthod, therefore, we can reduce the number of times of the repetitive stimulation to avoid the data deviation appeared by testee’s tiredness. This experiment provides train of thoughts in processing EEG signals, and has important reference for BCI study based P300research.