Excision of Ocular Artifacts from EEG Using NVFF-RLS Adaptive Algorithm
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- 作者：Harish Kumar Garg ; Amit Kumar Kohli
- 关键词：EEG ; EOG ; Artifacts ; RLS ; Normalized least mean square (NLMS) ; Numeric variable forgetting factor (NVFF) ; Fixed forgetting factor (FFF) ; Fixed step ; size (FSS) ; Generalized variable step ; size (GVSS) algorithm
- 刊名：Circuits, Systems, and Signal Processing
- 出版年：2017
- 出版时间：January 2017
- 年：2017
- 卷：36
- 期：1
- 页码：404-419
- 全文大小：
- 刊物类别：Engineering
- 刊物主题：Circuits and Systems; Electrical Engineering; Signal,Image and Speech Processing; Electronics and Microelectronics, Instrumentation;
- 出版者：Springer US
- ISSN：1531-5878
- 卷排序：36
文摘
This paper presents a technique for the removal of ocular artifacts from electro-encephalogram (EEG) by using adaptive filtering. The major concern is electro-oculogram (EOG) signal present in a recorded EEG signal, which appears due to abrupt eye movements. In the presented method, we use separately recorded horizontal EOG (HEOG) and vertical EOG (VEOG) signals as two reference inputs, which are processed using finite impulse response (FIR) filters. The linear filter coefficients are adaptively updated using a numerical variable forgetting factor (NVFF) recursive least squares (RLS) algorithm, which tracks nonstationary EOG signals. Subsequently, the processed HEOG and VEOG signals are subtracted from recorded EEG signal to obtain an artifact-free EEG signal. Simulation is conducted using synthetic EEG signal corrupted by noise, synthetic HEOG and VEOG signals. The real-time recorded EEG signal (corrupted by EOG and noise) is also refined using the separately recorded reference EOG signals and FIR filtering technique. For synthetic and real-time signals, the simulation results are presented to demonstrate that linear NVFF-RLS algorithm-based artifact and noise excision technique outperforms conventional fixed forgetting factor RLS, fixed step-size NLMS and generalized variable step-size NLMS algorithms, in terms of the reduction in mean-squared error, under low as well as high signal-to-noise ratio conditions.