Title | Application of a hybrid wavelet feature selection method in the design of a self-paced brain interface system |
Publication Type | Journal Article |
Year of Publication | 2007 |
Authors | Fatourechi, M., G. E. Birch, and R. K. Ward |
Journal | J Neuroeng Rehabil |
Volume | 4 |
Pagination | 11 |
Abstract | BACKGROUND: Recently, successful applications of the discrete wavelet transform have been reported in brain interface (BI) systems with one or two EEG channels. For a multi-channel BI system, however, the high dimensionality of the generated wavelet features space poses a challenging problem. METHODS: In this paper, a feature selection method that effectively reduces the dimensionality of the feature space of a multi-channel, self-paced BI system is proposed. The proposed method uses a two-stage feature selection scheme to select the most suitable movement-related potential features from the feature space. The first stage employs mutual information to filter out the least discriminant features, resulting in a reduced feature space. Then a genetic algorithm is applied to the reduced feature space to further reduce its dimensionality and select the best set of features. RESULTS: An offline analysis of the EEG signals (18 bipolar EEG channels) of four able-bodied subjects showed that the proposed method acquires low false positive rates at a reasonably high true positive rate. The results also show that features selected from different channels varied considerably from one subject to another. CONCLUSION: The proposed hybrid method effectively reduces the high dimensionality of the feature space. The variability in features among subjects indicates that a user-customized BI system needs to be developed for individual users. |
URL | http://dx.doi.org/10.1186/1743-0003-4-11 |
DOI | 10.1186/1743-0003-4-11 |