In the study of brain computer interfaces,a method based on empirical mode decomposition(EMD) and Hilbert transformation was proposed. The method was used for the feature extraction of electroencephalogram. In this method,the basis function was selected automatically according to the local features of signal during the transforming process,the Hilbert spectrum was obtained in each period,and the statistical characteristics in time-frequency window were considered as features. Then the optimal feature sets were formed by the Fisher distance rule and put into the classification. The performance of the eigenvector was evaluated by separability and recognition accuracy with the data set of BCI 2003 competition,and classification results proved the effectiveness of the proposed method.
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