脑电信号伪迹去除算法综述

Removing Artifacts from EEG Signals: A Review

  • 摘要: 脑电图(Electroencephalography, EEG)是通过精密放大仪器将脑部微弱的生物电位加以放大记录而获得的图形。因其具有安全无创、成本低廉、时间分辨率高等优点广泛应用于医疗诊断和神经科学研究等领域。然而脑电信号幅值微弱,在采集过程中容易受到外部环境和生理活动的影响,实际获得的脑电信号通常混有大量噪声,其中由被试者生理活动引起的噪声在时域或频域上与脑电信号存在重叠,简单的预处理手段难以将它们分离,因此能够有效去除这些噪声的脑电伪迹去除算法一直是脑机领域的研究热点。传统的伪迹去除算法包括回归、小波变换、经验模态分解、盲源分离等,它们通过信号自身的时频特征或信号间的统计特征进行伪迹分离,在脑电图的应用发展中发挥了重要的作用。然而由于伪迹成分复杂,脑电伪迹去除研究中尚不存在一种可以适用所有情况的去伪迹方法,为实际应用中目标和算法之间的匹配问题带来不必要的选择负担。为此,文中首先总结了伪迹的成因和类别,并探讨了不同生理伪迹的形态特点。之后,对现有的国内外脑电去伪迹方法进行了归纳总结,讨论了不同算法在去除伪迹方面的优缺点及适用性差异,为今后不同领域的研究人员选择适用的脑电伪迹去除算法提供理论依据。最后分析了当前研究存在的一些问题,展望了未来脑电去伪迹研究的发展方向。

     

    Abstract: ‍ ‍An electroencephalogram (EEG) records the brain biological potential by collecting electrical signals from the human scalp through precision amplification instruments. It is widely used in medical diagnosis and scientific research fields for its advantages of safety, low cost, and high temporal resolution. However, the amplitude of an EEG signal is weak, and the actual EEG signal is normally mixed with noises. In general, the EEG signal is vulnerable to the external environment and physiological activities during the process of acquisition, which means it can be contaminated easily. Among these noises, the one caused by physiological activities of the subjects overlaps with the pure EEG signals in the time or frequency domain, making it difficult to separate them from the EEG signal with simple preprocessing methods. Consequently, algorithms for the recognition and removal of EEG artifacts, able to effectively remove the noises, have been a research focus in the brain-computer field. Conventional algorithms for the removal of artifacts include regression, wavelet transform, empirical mode decomposition, and blind source separation. They separate artifacts and the pure EEG signal based on the time-frequency characteristics of the signal itself or the statistical characteristics between signals, and play an important role in the development and application of EEGs. However, although many studies have been conducted on EEG artifact removal, a method that can be applied to all cases has not been developed owing to the complexity of artifact components. This causes an unnecessary burden of choice for the matching between target and algorithm in practical applications. This paper contributes to the solution of the problem. First, the paper summarizes the causes and categories of artifacts, and explores the morphological characteristics of different physiological artifacts. This enables researchers from different fields to have a more detailed understanding of artifacts. Second, various advanced methods for removing artifacts from EEG signals globally are summarized. Further, the advantages, disadvantages, and differences in applicability of those methods in terms of artifact removal performance are discussed. This can provide a theoretical basis for researchers in different fields to choose suitable algorithms for removing EEG artifacts in the future. Finally, some existing problems in current research are analyzed, and the development direction of the research on EEG artifact removal is discussed.

     

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