Comparison of wrist motion classification methods using surface electromyogram

JEONG Eui-chul, KIM Seo-jun, SONG Young-rok, LEE Sang-min

(Department of Electronic Engineering, Inha University, yonghyun-dong, Incheon 402-751, Korea)

Abstract:The Gaussian mixture model (GMM), k-nearest neighbor (k-NN), quadratic discriminant analysis (QDA), and linear discriminant analysis (LDA) were compared to classify wrist motions using surface electromyogram (EMG). Effect of feature selection in EMG signal processing was also verified by comparing classification accuracy of each feature, and the enhancement of classification accuracy by normalization was confirmed. EMG signals were acquired from two electrodes placed on the forearm of twenty eight healthy subjects and used for recognition of wrist motion. Features were extracted from the obtained EMG signals in the time domain and were applied to classification methods. The difference absolute mean value (DAMV), difference absolute standard deviation value (DASDV), mean absolute value (MAV), root mean square (RMS) were used for composing 16 double features which were combined of two channels. In the classification methods, the highest accuracy of classification showed in the GMM. The most effective combination of classification method and double feature was (MAV, DAMV) of GMM and its classification accuracy was 96.85%. The results of normalization were better than those of non-normalization in GMM, k-NN, and LDA.

Key words:Gaussian mixture model; k-nearest neighbor; quadratic discriminant analysis; linear discriminant analysis; electromyogram (EMG); pattern classification; feature extraction