A Novel Denoising Method for Ship-Radiated Noise

Ship-radiated noise (SN) is one of the most critical signals in the complex marine environment; however, it is inevitably contaminated by the marine environment’s noise as well as noise from other equipment. Thus, the feature extraction and identification of SN becomes very arduous. This paper proposes a denoising method for SN based on successive variational mode decomposition (SVMD), the dual-threshold analysis based on fuzzy dispersion entropy (FuDE) and wavelet packet denoising (WPD), termed SVMD-FuDE-WPD. First, SVMD adaptively decomposes SN into certain intrinsic mode functions (IMFs), which can solve the parameter selection problem of variational mode decomposition (VMD) and suppress the mode mixing of empirical mode decomposition (EMD). After that, the FuDE-based dual-threshold analysis is used to accurately classify IMFs into signal IMFs, noise–signal IMFs and noise IMFs. Finally, the denoised signal could be obtained by reconstructing the signal IMFs and noise–signal IMFs that were denoised using WPD. The classical simulation experiments demonstrate the effectiveness of the proposed denoising method, which performs better than the other four existing denoising methods. And the measured SN experiments show that the attractor trajectories of the proposed method are smoother and more regular, which verifies the effectiveness of the proposed method.