Research on Empirical Mode Decomposition Denoising Under Multiwavelet Packet

The Signal to Noise Ratio(SNR)of the denoised signal is low by using the approaches of traditional denoising method based on wavelet analysis and the method based on Empirical Mode Decomposition(EMD).Aiming at this problem,this paper proposes an interval iterative threshold of EMD denoising method under the frame of multiwavelet packets.The input signal with noise is preprocessed firstly.After the signal is transformed into the multidimensional form,the paper devises a new thresholding function which is inspired by the hard and the soft thresholding function.The multi-wavelet coefficients in the last level is denoised by the new thresholding function and the one dimensional wavelet coefficients is gotten,which is followed by the Intrinsic Mode Function(IMF)deposed by this method.The denoised signal is acquired by reconstruction.Simulation results show that the novel method can improve the SNR by about 2.5 dB and the Mean Squared Error(MSE)also decreases to 0.000 7compared with the traditional methods,and the ability of denoising is better.