单通道视觉诱发脑电的单次提取方法研究

针对单通道脑电信号单次提取识别率较低的问题,提出了一种正交B样条小波变换与Fisher线性判别相结合的方法,提高了视觉诱发电位P300的单次提取识别率。首先采用相干平均和小波变换的方法对脑电信号进行预处理,然后根据脑电信号的时-频特性及视觉诱发电位的锁时关系,提取出表征P300的8维小波系数模板,再次利用模板对单次样本进行特征提取,最后根据Fisher线性判别对测试样本进行分类识别,判断单次输入是否为视觉诱发脑电信号。实验结果表明,该方法对单次样本P300的平均识别率为95.10%。

Study on single-trial feature extraction method of single-channel visual evoked potential

Aiming at the low recognition rate problem in single-trial feature extraction of P300,a method based on orthogonal B-spline wavelet transform and Fisher linear Discriminant(FLD) was proposed.First,a method of coherent averaging combined with wavelet transform is introduced to preprocess the trial,and according to the time-frequency characteristics and time-locked relationship in VEP,a 8-dimension wavelet coefficient template representing P300 is constructed;then the features of the trial are extracted using the template;finally,a Fisher linear classifier is designed,which determines whether a single input is visual evoked EEG or not.Experiment results demonstrate that the method based on orthogonal B-spline wavelet transform and FLD has a good average recognition rate as high as 90% for the P300 identification.