Improving Generalization Based on l1-Norm Regularization for EEG-Based Motor Imagery Classification

Multichannel electroencephalography (EEG) is widely used in typical brain-computer interface (BCI) systems. In general, a number of parameters are essential for a EEG classification algorithm due to redundant features involved in EEG signals. However, the generalization of the EEG method is often ad...

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Main Authors: Yuwei Zhao, Jiuqi Han, Yushu Chen, Hongji Sun, Jiayun Chen, Ang Ke, Yao Han, Peng Zhang, Yi Zhang, Jin Zhou, Changyong Wang
Format: Article
Language:English
Published: Frontiers Media S.A. 2018-05-01
Series:Frontiers in Neuroscience
Subjects:
Online Access:http://journal.frontiersin.org/article/10.3389/fnins.2018.00272/full
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author Yuwei Zhao
Jiuqi Han
Yushu Chen
Hongji Sun
Jiayun Chen
Jiayun Chen
Ang Ke
Ang Ke
Yao Han
Yao Han
Peng Zhang
Peng Zhang
Yi Zhang
Jin Zhou
Changyong Wang
author_facet Yuwei Zhao
Jiuqi Han
Yushu Chen
Hongji Sun
Jiayun Chen
Jiayun Chen
Ang Ke
Ang Ke
Yao Han
Yao Han
Peng Zhang
Peng Zhang
Yi Zhang
Jin Zhou
Changyong Wang
author_sort Yuwei Zhao
collection DOAJ
description Multichannel electroencephalography (EEG) is widely used in typical brain-computer interface (BCI) systems. In general, a number of parameters are essential for a EEG classification algorithm due to redundant features involved in EEG signals. However, the generalization of the EEG method is often adversely affected by the model complexity, considerably coherent with its number of undetermined parameters, further leading to heavy overfitting. To decrease the complexity and improve the generalization of EEG method, we present a novel l1-norm-based approach to combine the decision value obtained from each EEG channel directly. By extracting the information from different channels on independent frequency bands (FB) with l1-norm regularization, the method proposed fits the training data with much less parameters compared to common spatial pattern (CSP) methods in order to reduce overfitting. Moreover, an effective and efficient solution to minimize the optimization object is proposed. The experimental results on dataset IVa of BCI competition III and dataset I of BCI competition IV show that, the proposed method contributes to high classification accuracy and increases generalization performance for the classification of MI EEG. As the training set ratio decreases from 80 to 20%, the average classification accuracy on the two datasets changes from 85.86 and 86.13% to 84.81 and 76.59%, respectively. The classification performance and generalization of the proposed method contribute to the practical application of MI based BCI systems.
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spelling doaj.art-09899d003a514ad7aac4e52a8eede0f42022-12-21T18:58:30ZengFrontiers Media S.A.Frontiers in Neuroscience1662-453X2018-05-011210.3389/fnins.2018.00272347848Improving Generalization Based on l1-Norm Regularization for EEG-Based Motor Imagery ClassificationYuwei Zhao0Jiuqi Han1Yushu Chen2Hongji Sun3Jiayun Chen4Jiayun Chen5Ang Ke6Ang Ke7Yao Han8Yao Han9Peng Zhang10Peng Zhang11Yi Zhang12Jin Zhou13Changyong Wang14Department of Neural Engineering and Biological Interdisciplinary Studies, Institute of Military Cognition and Brain Sciences, Academy of Military Medical SciencesBeijing, ChinaDepartment of Neural Engineering and Biological Interdisciplinary Studies, Institute of Military Cognition and Brain Sciences, Academy of Military Medical SciencesBeijing, ChinaDepartment of Neural Engineering and Biological Interdisciplinary Studies, Institute of Military Cognition and Brain Sciences, Academy of Military Medical SciencesBeijing, ChinaDepartment of Neural Engineering and Biological Interdisciplinary Studies, Institute of Military Cognition and Brain Sciences, Academy of Military Medical SciencesBeijing, ChinaDepartment of Neural Engineering and Biological Interdisciplinary Studies, Institute of Military Cognition and Brain Sciences, Academy of Military Medical SciencesBeijing, ChinaCollege of Life Science and Technology, Huazhong Agricultural UniversityWuhan, ChinaDepartment of Neural Engineering and Biological Interdisciplinary Studies, Institute of Military Cognition and Brain Sciences, Academy of Military Medical SciencesBeijing, ChinaNeural Interface & Rehabilitation Technology Research Center, Huazhong University of Science and TechnologyWuhan, ChinaDepartment of Neural Engineering and Biological Interdisciplinary Studies, Institute of Military Cognition and Brain Sciences, Academy of Military Medical SciencesBeijing, ChinaStem Cell and Tissue Engineering Lab, Beijing Institute of Transfusion MedicineBeijing, ChinaDepartment of Neural Engineering and Biological Interdisciplinary Studies, Institute of Military Cognition and Brain Sciences, Academy of Military Medical SciencesBeijing, ChinaNeural Interface & Rehabilitation Technology Research Center, Huazhong University of Science and TechnologyWuhan, ChinaDepartment of Neural Engineering and Biological Interdisciplinary Studies, Institute of Military Cognition and Brain Sciences, Academy of Military Medical SciencesBeijing, ChinaDepartment of Neural Engineering and Biological Interdisciplinary Studies, Institute of Military Cognition and Brain Sciences, Academy of Military Medical SciencesBeijing, ChinaDepartment of Neural Engineering and Biological Interdisciplinary Studies, Institute of Military Cognition and Brain Sciences, Academy of Military Medical SciencesBeijing, ChinaMultichannel electroencephalography (EEG) is widely used in typical brain-computer interface (BCI) systems. In general, a number of parameters are essential for a EEG classification algorithm due to redundant features involved in EEG signals. However, the generalization of the EEG method is often adversely affected by the model complexity, considerably coherent with its number of undetermined parameters, further leading to heavy overfitting. To decrease the complexity and improve the generalization of EEG method, we present a novel l1-norm-based approach to combine the decision value obtained from each EEG channel directly. By extracting the information from different channels on independent frequency bands (FB) with l1-norm regularization, the method proposed fits the training data with much less parameters compared to common spatial pattern (CSP) methods in order to reduce overfitting. Moreover, an effective and efficient solution to minimize the optimization object is proposed. The experimental results on dataset IVa of BCI competition III and dataset I of BCI competition IV show that, the proposed method contributes to high classification accuracy and increases generalization performance for the classification of MI EEG. As the training set ratio decreases from 80 to 20%, the average classification accuracy on the two datasets changes from 85.86 and 86.13% to 84.81 and 76.59%, respectively. The classification performance and generalization of the proposed method contribute to the practical application of MI based BCI systems.http://journal.frontiersin.org/article/10.3389/fnins.2018.00272/fullmotor imageryelectroencephalography (EEG)classificationl1-norm regularizationgeneralization
spellingShingle Yuwei Zhao
Jiuqi Han
Yushu Chen
Hongji Sun
Jiayun Chen
Jiayun Chen
Ang Ke
Ang Ke
Yao Han
Yao Han
Peng Zhang
Peng Zhang
Yi Zhang
Jin Zhou
Changyong Wang
Improving Generalization Based on l1-Norm Regularization for EEG-Based Motor Imagery Classification
Frontiers in Neuroscience
motor imagery
electroencephalography (EEG)
classification
l1-norm regularization
generalization
title Improving Generalization Based on l1-Norm Regularization for EEG-Based Motor Imagery Classification
title_full Improving Generalization Based on l1-Norm Regularization for EEG-Based Motor Imagery Classification
title_fullStr Improving Generalization Based on l1-Norm Regularization for EEG-Based Motor Imagery Classification
title_full_unstemmed Improving Generalization Based on l1-Norm Regularization for EEG-Based Motor Imagery Classification
title_short Improving Generalization Based on l1-Norm Regularization for EEG-Based Motor Imagery Classification
title_sort improving generalization based on l1 norm regularization for eeg based motor imagery classification
topic motor imagery
electroencephalography (EEG)
classification
l1-norm regularization
generalization
url http://journal.frontiersin.org/article/10.3389/fnins.2018.00272/full
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