Title
Semi-supervised feature extraction for EEG classification
Abstract
Two semi-supervised feature extraction methods are proposed for electroencephalogram (EEG) classification. They aim to alleviate two important limitations in brain---computer interfaces (BCIs). One is on the requirement of small training sets owing to the need of short calibration sessions. The second is the time-varying property of signals, e.g., EEG signals recorded in the training and test sessions often exhibit different discriminant features. These limitations are common in current practical applications of BCI systems and often degrade the performance of traditional feature extraction algorithms. In this paper, we propose two strategies to obtain semi-supervised feature extractors by improving a previous feature extraction method extreme energy ratio (EER). The two methods are termed semi-supervised temporally smooth EER and semi-supervised importance weighted EER, respectively. The former constructs a regularization term on the preservation of the temporal manifold of test samples and adds this as a constraint to the learning of spatial filters. The latter defines two kinds of weights by exploiting the distribution information of test samples and assigns the weights to training data points and trials to improve the estimation of covariance matrices. Both of these two methods regularize the spatial filters to make them more robust and adaptive to the test sessions. Experimental results on data sets from nine subjects with comparisons to the previous EER demonstrate their better capability for classification.
Year
DOI
Venue
2013
10.1007/s10044-012-0298-2
Pattern Analysis & Applications
Keywords
Field
DocType
Semi-supervised learning,Feature extraction EEG classification,Extreme energy ratio,Regularization,Density ratio
Data set,Semi-supervised learning,Pattern recognition,Discriminant,Brain–computer interface,Feature extraction,Regularization (mathematics),Artificial intelligence,Machine learning,Calibration,Mathematics,Covariance
Journal
Volume
Issue
ISSN
16
2
1433-7541
Citations 
PageRank 
References 
12
0.62
27
Authors
2
Name
Order
Citations
PageRank
Wenting Tu1859.48
Shiliang Sun21732115.55