Identification of motions of the neck and shoulders using the electromyographic (EMG) signal was investigated in this study. Three discrimination methods, the Euclidean distance measure (Z3M), the weighted distance measure ( WLIhf) and the modiJied maximum likelihood method (MMLM), were used to compare the conventional autoregressive (AR) and cepal coef$cients with closely positioned (Gtype) and separately located (Stype) electrode arrangements. Surface electrodes were bilateral[v located on and between the sternocleidomastoid and the upper trapezius muscles. The EMG signals obtained during 20 repetitions of 10 motions were analysed for each subject. Results from nine subjects showed that the mean recognition rate of the cepstral coefficients was at least 5% better than that of the AR coefficients for the Stype signals, while the improvement was less obvious for the Gtype signals. The MMLM obtained the best discrimination results of the three discrimination methods. The Stype signals achieved higher recognition rates than the Gtype signals in most cases. Among the various combinations of feature sets, classi@s and electrode arrangements proposed in this study, the combination of the cepstral coefjcients and the MMI,M with the Stype arrangement achieved the best discrimination efjcienq.
The proper choice of five of 10 motions raised the recognition rate to more than 97%. @@right 0 1996 Else&r Science Ltd for ZPEMB.