Background: Brain responds in a short timeframe (with certain delay) after the request for doing a motor imagery task and therefore it is most likely that the individual not focus continuously on the task at entire interval of data acquisition time or even think about other things in a very short time slice. In this paper, an effective brain-computer interface (BCI) system is presented based on the optimal timeframe selection of brain signals. Methods: To prove the stated claim, various timeframes with different durations and delays selected based on a specific rule from electroencephalography (EEG) signals recorded during right/left hand motor imagery task and subsequently, feature extraction and classification are done. Results: Implementation results on the 2 well-known datasets termed Graz 2003 and Graz 2005; shows that the smallest systematically created timeframe of data acquisition interval have had the best results of classification. Using this smallest timeframe, the classification accuracy increased up to 91.43% for Graz 2003 and 88.96%, 83.64% and 84.86% for O3, S4 and X11 subjects of Graz 2005 database respectively. Conclusion: Removing the additional information in which the individual does not focus on the motor imagery task and utilizing the most distinguishing timeframe of EEG signals that correctly interpret individual intentions improves the BCI system performance.
展开▼
