Artifact reduction from electroencephalographic (EEG) signals is an important process in the numerical analysis of brain activities. In general, independent component analysis (ICA) is employed for artifact reduction from multichannel EEG devices. On the other hand, single-channel EEG devices have recently become attractive because of their usability for measurement and their portability. However, it is ill-defined problem to design a numerical approach for eye-blink artifact reduction from single-channel EEG signals. In this paper, we therefore propose a new artifact reduction method based on 2-step nonnegative matrix factorization (NMF) for single-channel EEG signals. In an experiment, we conducted 2-step NMF to reject eye-blink artifacts using single-channel EEG signals recorded at Fp1. We also applied ICA to multichannel EEG signals and compared the results with those obtained by the proposed method. The experimental results show a relatively high signal-to-noise ratio (SNR) between the signals reconstructed using the proposed method and those obtained by ICA. Moreover, we confirm the coefficient of correlation of over 99% for estimating the recorded EEG signals by the proposed method.
2014 Research Institute of Signal Processing, Japan