Feature Extraction of Ship-Radiated Noise Based on Permutation Entropy of the Intrinsic Mode Function with the Highest Energy

Abstract

Abstract:In order to solve the problem of feature extraction of underwater acoustic signals in complex ocean environment, a new method for feature extraction from ship-radiated noise is presented based on empirical mode decomposition theory and permutation entropy. It analyzes the separability for permutation entropies of the intrinsic mode functions of three types of ship-radiated noise signals, and discusses the permutation entropy of the intrinsic mode function with the highest energy. In this study, ship-radiated noise signals measured from three types of ships are decomposed into a set of intrinsic mode functions with empirical mode decomposition method. Then, the permutation entropies of all intrinsic mode functions are calculated with appropriate parameters. The permutation entropies are obviously different in the intrinsic mode functions with the highest energy, thus, the permutation entropy of the intrinsic mode function with the highest energy is regarded as a new characteristic parameter to extract the feature of ship-radiated noise. After that, the characteristic parameters-namely, the energy difference between high and low frequency, permutation entropy, and multi-scale permutation entropy-are compared with the permutation entropy of the intrinsic mode function with the highest energy. It is discovered that the four characteristic parameters are at the same level for similar ships, however, there are differences in the parameters for different types of ships. The results demonstrate that the permutation entropy of the intrinsic mode function with the highest energy is better in separability as the characteristic parameter than the other three parameters by comparing their fluctuation ranges and the average values of the four characteristic parameters. Hence, the feature of ship-radiated noise can be extracted efficiently with the method.

A Novel Feature Extraction Method for Ship-Radiated Noise Based on Variational Mode Decomposition and Multi-Scale Permutation Entropy

“…(1) Compared with [31], the proposed method uses VMD instead of EMD. Simulation results show that the VMD method is more accurate and effective than EMD and EEMD methods.…”

“…(2) Compared with [31], the proposed method uses MPE instead of PE. PE can quantify the complexity only in one scale, while the MPE is used to extract features in different scales.…”

“…As shown in the Table 4, the first and second types are in the same level among them. According to the parameter settings of PE in [31], we select 4 as the embedding dimension and 1 as the time delay, the MPE of IMF with the highest energy by VMD is shown in Figure 7. As shown in the Figure 7, the MPE of IMF with the highest energy increases with the increases of scale, and the difference of MPE also increases with the increases of scale.…”

Denoising and Feature Extraction Algorithms Using NPE Combined with VMD and Their Applications in Ship-Radiated Noise

“…As shown in Figure 8, 8 IMFs of each ship are listed in descending order by frequency. In this paper, PIMF is the IMF with the most energy intensity, which has the same definition in [11,29]. The distribution of PIMF for three kinds of SN is listed in Table 10.…”

“…In research [28], a feature extraction algorithm for partial discharge is proposed using sample entropy combined with VMD. In the field of underwater acoustic signal processing, PE and multi-scale PE (MPE), as complexity features, are used to extract complexity features of SN combined with EMD and VMD respectively in [11,29]. It has been verified that the two feature extraction algorithms outperform the traditional feature extraction algorithms [30,31].…”