A Novel Stimulation Method Combined of Time and Frequency Coded for SSVEP-Based BCI

• Main Authors: Shan-Pei Wu, 吳姍蓓
• Other Authors: Kuo-Kai Shyu
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/12844346418887963176

碩士 === 國立中央大學 === 電機工程研究所 === 100 === This study proposes a novel stimulation method for steady state visual evoked potential-based brain computer interfaces (SSVEP-based BCIs). The general SSVEP response is induced by a flicker flashing at a fixed frequency. However, visual fatigue evoked by durative stimuli will reduce the amplitude of SSVEP response and make the user uncomfortable. The new coding approach combined of the frequency-locked and time-locked features of SSVEP can eliminate these disadvantages. The flickers will flash for 1 second and turn off respectively for 0.5, 1 and 1.5 seconds by turns. The cycles of the stimulus sequences may cause the corresponding reaction, and the SSVEP energy may appear as periodic variations. This feature will be used in the classification. Finally, the experiment results demonstrate that the SSVEP induced by the proposed method do have the periodic property and can be used in the BCI system.