摘要
提出基于多频率刺激源诱发SSVEP的脑机接口(BCI)系统.针对脑电信号的微弱性和非平稳性特点,在对其进行预处理和空间滤波的基础上,采用平滑伪Wigner-Ville分布的时频分析方法将时间窗口长度内的脑电信号转换为时间-频率分布的信号.分类汇总视觉刺激时间内的脑电频率,并提取脑电信号中的最大频率成分作为目标频率.实验结果表明:随着分析时间窗的增大,平滑伪Wigner-Ville时频分析方法具有一定的优势.当时间窗为4s时,其分类准确率达98.29%,信息传输率达28.01bits/min,超过经典的典型相关分析(CCA)和功率谱密度分析(PSDA)的结果.
The multi-frequencies stimulus brain-computer interface(BCI)system based on SSVEP was proposed.Electroencephalography(EEG)is preprocessed and spatial filtered firstly due to its weakness and non-stationary characteristics.The time-frequency analysis method of smoothed pseudo Wigner-Ville distribution was used to extract the maximum frequency components of the EEG signal as the target frequency,while the EEG signal in the length of time window was converted into a time-frequency distribution signal and the visual stimuli EEG frequency time was classified and summarized.As results,the time-frequency analysis method of SPWVD shows advantages with the increase of the length of time windows.When the length of time window reaches 4s,the classification accuracy of SPWVD reaches 98.29%and the information transmission rate reaches 28.01bit/min,which is superior to the results by the classic methods of canonical correlation analysis(CCA)and power spectral-density analysis(PSDA),respectively.
引文
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