In this paper, we present a hybrid de-noising method to remove the noise of electrostatic monitoring signal. Firstly,
we introduce the method which combines the advantage of the median filter and the wavelet multilevel threshold
de-noise based on the Birge-Massart strategy, then present one methodology to compute the signal-to-noise by wavelet
decomposing, and take the improved signal-to-noise as the evaluation index to compare the de-noise methods. The two
illustrative examples are employed to validate the effectiveness of the hybrid method proposed in the paper.