A Comparative Study of Linear and Non-Linear Classifiers in Sensory Motor Imagery Based Brain Computer Interface

Abstract

Over the period of 4–5 decades of the field electrophysiology on neural signal events in single cell recording, it can be concluded that there is production of far field potentials containing near synchronous field patterns might reach at the scalp electrodes. These neural signals then can be analyzed and converted into the control signals for computers and other electronic devices. Electroencephalography (EEG) is a method to acquire these neural signals from the scalp of human brain. EEG signals are simple, economical and have high temporal resolution properties. These properties make it advantageous to use widely in the medical as well as non-medical applications. The event related synchronization and desynchronization (ERS/ERD) pattern present in EEG during sensory motor imagery (SMI) process over the cortical area is an important feature to take BCI towards realistic approach. The accurate classification of these ERS/ERD pattern present in EEG signal is dependent on classification accuracy of different classifiers. So, the objective of the paper is to analyze the classification accuracy of linear and non-linear classifiers used for BCI system design. This paper also presents the comparative study of linear (Linear discriminant analysis and Support Vector Machine) and non-linear classifiers (Bayesian and Radial Basis Function-Support Vector Machine) using BCI competition IV dataset 2a. The result concluded that linear classifiers (LDA and SVM) have outperformed the non-linear classifiers on EEG data with the average performance across subjects 75.26±12.23, 72.42±11.12.