作　　者： ; ; ;

机构地区： 中国科学技术大学信息科学技术学院电子工程与信息科学系

出　　处： 《电子测量与仪器学报》 2008年第6期17-21,共5页

摘　　要： 眼电伪差的幅度远大于脑电信号的幅度,会严重影响对脑电信号分析,必须有效地去除。本文利用Hilbert-Huang变换的多分辨率分析特征,根据脑电信号中眼电伪差的时频特性,提出了根据固有模态函数统计特性确定阈值的Hil-bert-Huang变换阈值眼电伪差去除方法。对受到眼电伪差干扰的脑电信号进行经验模式分解,利用Hilbert变换计算不同固有模态函数的瞬时频率,将瞬时频率小于3 Hz固有模态函数的值置零,对瞬时频率小于16 Hz的固有模态函数进行阈值处理。利用处理后的固有模态函数重建脑电信号,实现眼电伪差的去除。实验结果表明该方法对去除脑电信号中的眼电伪差是非常有效的,而且对脑电信号影响很小。 Ocular artifacts whose amplitude is much larger than Electroencephalogram （EEG） sometimes obscure the smaller amplitudeunderlying brainwave activity, making the brainwave activity difficult to be inspected. Therefore, the ocular artifacts must be removed from EEG effectively. According to the time-frequency properties of the ocular artifacts, a threshold method of ocular artifacts removal was proposed, which is based on the characteristics of multi-resolution analysis of HHT and a threshold value determined by the statistical characteristics of intrinsic mode function. First, the EEG contaminated by ocular artifacts is decomposed into intrinsic mode functions. Then the instantaneous frequency of each intrinsic mode function is computed by Hilbert transform respectively. If all the instantaneous frequencies of an intrinsic mode function are less than 3 Hz, then the value of the intrinsic mode function is set to zero. If all the instantaneous frequencies of an intrinsic mode function are less than 16 Hz, then the value of intrinsic mode function, that is greater than a threshold, is set to zero. Computing the sum of all intrinsic mode functions, we can obtain corrected EEG. Experimental results show that this method is effective; can remove most ocular artifacts in EEG and only distort EEG slightly,was effective.

关 键 词： 经验模式分解 多分辨率分析 瞬时频率 眼电伪差

领　　域： [电子电信] [电子电信]