ANALYSIS OF EEG SIGNALS WITH CHANGING SPECTRA USING A SHORT-WORD KALMAN ESTIMATOR
ANALYSIS OF EEG SIGNALS WITH CHANGING SPECTRA USING A SHORT-WORD KALMAN ESTIMATOR
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DOI:
10.1016/0025-5564(77)90026-8
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发表时间:
1977-01-01
影响因子:
4.3
通讯作者:
BOHLIN, T
中科院分区:
文献类型:
--
作者:
BOHLIN, T
A new method was described for the numerical analysis of EEG signals, whose spectral distributions vary with time. The variation need not be slow. The theory described a sampled EEG by an autoregressive series of high order with stochastic coefficients having independent increments. The coefficients were augmented as state variables and could thus be estimated in real time by a special Kalman filter. This raised 2 problems. The Riccati equation depended on the signal and was numerically unstable. Specifications for tuning the filter were unknown; the essential parameter was the rate of change of the stochastic coefficients. For solutions, a numerically stable algorithm was derived (not square-root filtering), and the rate of change was estimated according to maximum likelihood. This defined an index of nonstationarity, the value of which is fundamental for the analysis. Applications to recorded EEG signals [human] demonstrated the feasibility of the method.