多层频时空特征提取的RSVP目标分类算法

Multilayer Classification Algorithm of Frequency-Time-Space Feature Extraction on RSVP Task

  • 摘要: 由于事件相关电位(ERP)信噪比低、变异性强,其在大脑皮层所体现的空间−时间信息分布在不同RSVP范式下的分布差异较大,并且传统基于CSP或LDA的单试次解码算法在不同数据集下分类性能不稳定,分类模型鲁棒性在数据集间有限.对此,从频−时−空域多个角度出发,通过设计两个交替迭代优化的空时域滤波器进行特征提取,提出了一种多层频时空ERP特征提取的目标分类算法(STAEE)以增强RSVP-BCI的解码性能.算法共分为滤波器组模块、时间窗分解模块、空时域滤波模块和感兴趣区域选择模块.在两个公共RSVP数据集的分类任务中,相较于结构化判别分析(HDCA)、共空域模式(CSP)、滤波器组共空域模式(FBCSP)以及空时判别分析(STDA)4个基准算法,所提出的STAEE算法获得了更高的曲线下面积(AUC),这表明该算法能够有效克服ERP在不同数据集分布的变异性,提升识别系统的分类性能.

     

    Abstract: Rapid serial visual presentation (RSVP) is a brain-computer interface (BCI) paradigm based on event-related potential (ERP) detection. By decoding and classifying electroencephalogram (EEG) signals, this technology can be widely utilized in target search and interactive control tasks. Due to the behavior of ERP in strong variability and low signal-to-noise ratio (SNR), the distribution of spatiotemporal information varies greatly for classification reflected in the cerebral cortex for different subjects. And, the performance of traditional single-trial classification algorithms based on CSP or LDA is unstable for different datasets, the robustness of classification models is limited across datasets. In order to improve the decoding performance of RSVP-BCI, two spatiotemporal filters were designed and optimized by alternating iteration for feature extraction, and a spatiotemporal analysis for ERP extraction (STAEE) algorithm was proposed based on frequency-time-space domain perspectives. The STAEE algorithm was arranged to be consisted of a filter-bank module, a time-window decomposition module, a spatiotemporal filtering module and a region of interest (ROI) selection module. In two classification tasks of public RSVP dataset, the proposed STAEE algorithm can obtained higher area under curve (AUC) values than the four benchmark algorithms, including hierarchical discriminant component analysis (HDCA), common spatial pattern (CSP), filter bank common spatial pattern (FBCSP) and space-time discriminant analysis (STDA). The results show that the STAEE algorithm can effectively overcome the variability of ERP distribution across different datasets, and improve the classification performance of RSVP-BCI system.

     

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