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Journal of ZheJiang University (Engineering Science)  2024, Vol. 58 Issue (12): 2540-2546    DOI: 10.3785/j.issn.1008-973X.2024.12.013
    
Classification of group speech imagined EEG signals based on attention mechanism and deep learning
Yifan ZHOU1(),Lingwei ZHANG1,2,Zhengdong ZHOU1,*(),Zhi CAI1,Mengyao YUAN1,Xiaoxi YUAN1,Zeyi YANG1
1. State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
2. VeriSilicon Holdings (Nanjing) Co. Ltd, Nanjing 210000, China
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Abstract  

A classification method based on convolutional block attention module (CBAM) and Inception-V4 convolutional neural network was proposed to improve the classification accuracy of group EEG signals of imagined speech. CBAM was used to emphasize significant localized areas and extract distinctive features from the output feature map of convolutional neural network (CNN), so as to improve the classification performance of group EEG signals of imagined speech. The group EEG signals of imagined speech were converted into time-frequency images by short-time Fourier transform, then the images were used to train the Inception-V4 network incorporating with CBAM. Experiments on an open-accessed dataset showed that the proposed method achieved an accuracy of 52.2% in classifying six types of short words, which was 4.1 percentage points higher than that with Inception-V4 and was 5.9 percentage points higher than that with VGG-16. Furthermore, the training time can be reduced greatly with transfer learning.



Key wordsbrain-computer interface      electroencephalogram      speech imagery      deep learning      attention mechanism     
Received: 17 October 2023      Published: 25 November 2024
CLC:  TP 391  
Fund:  中国航空研究院首批揭榜挂帅项目(F2021109);上海航天科技创新基金资助项目 (SAST2019-121);南京航空航天大学科研与实践创新计划资助项目(xcxjh20210104);江苏高校优势学科建设工程资助项目(PAPD).
Corresponding Authors: Zhengdong ZHOU     E-mail: sz2201046@nuaa.edu.cn;zzd_msc@nuaa.edu.cn
Cite this article:

Yifan ZHOU,Lingwei ZHANG,Zhengdong ZHOU,Zhi CAI,Mengyao YUAN,Xiaoxi YUAN,Zeyi YANG. Classification of group speech imagined EEG signals based on attention mechanism and deep learning. Journal of ZheJiang University (Engineering Science), 2024, 58(12): 2540-2546.

URL:

https://www.zjujournals.com/eng/10.3785/j.issn.1008-973X.2024.12.013     OR     https://www.zjujournals.com/eng/Y2024/V58/I12/2540


基于注意力机制和深度学习的群体语言想象脑电信号分类

为了提高群体语言想象脑电信号的分类准确率,提出基于卷积块注意力模块(CBAM)和Inception-V4卷积神经网络的分类方法,其中CBAM被用于关注重要的局部区域,从卷积神经网络(CNN)输出的特征图中提取更加独特的特征,从而提升群体语言想象脑电信号的分类性能. 该方法首先利用短时傅里叶变换将群体语言想象脑电信号转换为时频图,然后使用这些图片对融合了CBAM机制的Inception-V4网络进行训练. 开源数据集上的实验结果表明,所提出的方法使得6类短词的分类准确率达到了52.2%,与基于Inception-V4的分类方法相比,分类准确率提高了4.1个百分点,与基于VGG-16的分类方法相比,分类准确率提高了5.9个百分点. 使用迁移学习也能够大幅缩短训练所需的时间.


关键词: 脑-机接口,  脑电图,  语言想象,  深度学习,  注意力机制 
Fig.1 Position of electrode for electroencephalogram signal acquisition
Fig.2 Time-frequency graph
Fig.3 Network framework of Inception-V4[16]
Fig.4 Attention structure of CBAM[18]
Fig.5 Structure of Inception-V4 network incorporating CBAM
Fig.6 Flow chart of classification method of group EEG signals of imagined speech based on CBAM and Inception-V4
Fig.7 Time-frequency diagram with different window lengths
Fig.8 Loss function curve with training steps for group EEG signals of imagined speech under different window lengths
Fig.9 Images through Grad-CAM
Fig.10 Classification confusion matrix of group EEG signals of imagined speech based on Inception-V4
位置注意力机制
STNECANetCBAM不使用
STEM后20.7%22.4%39.6%48.1%
Avg Pooling前49.3%49.5%52.2%
Tab.1 Comparison of accuracy of different attention mechanisms in different positions
网络模型分类形式A/%
VMD-RWE+SVM with RBF kernel[22]6分类38.2
Siamese neural network framework[11]6分类44.1
end-to-end Siamese neural network[23]6分类31.4
Deep CNN[24]6分类28.4
VGG-166分类46.3
本研究提出的融合CBAM的Inception-V4模型6分类52.2
Tab.2 Comparison of classification accuracy of group EEG signals of imagined speech
编号源域(已训练数据集)目标域(要训练数据集)使用网络tt/hA/%
1Correto公开数据集Inception-V416848.1
2ImageNet-1000数据集Correto公开数据集Inception-V417147.7
3Correto公开数据集改Inception-V417252.2
4BCI Competition IV-2b数据集[25]Correto公开数据集改Inception-V46951.8
Tab.3 Comparison of signal classification accuracy using transfer learning
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