The invention relates to an electroencephalogram
signal preprocessing method based on
particle swarm optimization (PSO), ensemble empirical mode
decomposition (EEMD) and
independent component analysis (ICA), and aims to improve the quality of electroencephalogram signals and enhance analyzability of the signals. The method comprises the following steps: firstly, carrying out EEMD (Ensemble Empirical Mode
Decomposition) on an original electroencephalogram
signal, generating a plurality of
noise auxiliary signals by adding
white noise with different intensities, carrying out EMD on each
noise auxiliary
signal, and then averaging intrinsic mode functions (IMF) of all the
noise auxiliary signals to obtain a final IMF, thereby reducing the problem of mode
aliasing and improving the reliability of the electroencephalogram signal. Useful components and noise components are preliminarily separated out; secondly, optimizing EEMD parameters by using a PSO
algorithm; a particle swarm is initialized, each particle represents a possible parameter combination (such as
Gaussian white noise standard deviation and noise adding times), a
fitness function is defined, a quality index of a signal is taken as a target, positions and speeds of the particles are iteratively updated, the parameter combination is optimized, and finally optimal parameters are applied to perform EEMD
decomposition, so that an optimized IMF is obtained. Therefore, the complexity of manual parameter adjustment is avoided, and the
decomposition accuracy and stability are improved. Then, the
sample entropy of each IMF is calculated, a
sample entropy threshold value is set, the IMFs with the
sample entropy values higher than the threshold value are screened out, IMF components with low information content are effectively removed, effective components with high information content are reserved, and the analyzability of the signals is further improved. And finally, combining the screened effective IMF component with the original electroencephalogram signal to generate a virtual multi-channel signal, performing
Fast ICA (
Independent Component Analysis), separating out independent electroencephalogram signal components, further removing noise, and improving the purity and the signal-to-noise ratio of the signal. Through the steps, the quality of the electroencephalogram signals can be remarkably improved, and a
solid foundation is provided for subsequent signal analysis and application.