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Entropy and Information Theory in Acoustics

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A special issue of Entropy (ISSN 1099-4300). This special issue belongs to the section "Multidisciplinary Applications".

Deadline for manuscript submissions: closed (31 May 2020) | Viewed by 35593

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Dr. Yuxing Li

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School of Automation and Information Engineering, Xi’an University of Technology, Xi’an 710048, China
Interests: fractal dimension; underwater signal processing; sensor signal processing; denoising; feature extraction; fault diagnosis; image processing
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Prof. Ning Xiang

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Graduate Program in Architectural Acoustics, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
Interests: architectural acoustics; binaural technology; ultrasonic measurement technology; acoustic sensing; Bayesian signal processing; automatic target recognition

Special Issue Information

Dear Colleagues,

Acoustics, as one of the earliest branches of physics, has penetrated into many other fields and formed independent branches of acoustics, such as underwater acoustics, architectural acoustics, engineering acoustics, physical acoustics, environmental acoustics, psychological acoustics, musical acoustics, etc. In many studies, entropy and information theory have been applied to many branches of acoustics. For example, in the field of underwater acoustics, entropy plays an important role in the detection, noise reduction, and feature extraction of underwater acoustic signals.

Manuscripts that address any aspects associated with entropy or information theory applications in acoustics are welcome. Manuscripts attempting the integration of entropy or information theory with other concepts and addressing the role of entropy or information theory in acoustics, and even in other fields, are particularly encouraged. Prospective authors are invited to submit high-quality original contributions and reviews to this Special Issue. Potential topics include but are not limited to entropy in acoustics; information theory in acoustics; and entropy and information theory in acoustics.

Dr. Yuxing Li
Prof. Ning Xiang
Guest Editors

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Keywords

entropy; information theory; acoustics; underwater acoustics; architectural acoustics; engineering acoustics; physical acoustics; environmental acoustics; psychological acoustics; musical acoustics; acoustic materials; acoustic sensing; acoustic imaging; acoustic signal processing

Related Special Issue

Entropy and Information Theory in Acoustics III in Entropy (9 articles)

Published Papers (10 papers)

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Research

16 pages, 414 KiB

Open AccessArticle

Underdetermined DOA Estimation for Wideband Signals via Focused Atomic Norm Minimization

by Juan Shi, Qunfei Zhang, Weijie Tan, Linlin Mao, Lihuan Huang and Wentao Shi

Entropy 2020, 22(3), 359; https://0-doi-org.brum.beds.ac.uk/10.3390/e22030359 - 20 Mar 2020

Cited by 9 | Viewed by 2789

Abstract

In underwater acoustic signal processing, direction of arrival (DOA) estimation can provide important information for target tracking and localization. To address underdetermined wideband signal processing in underwater passive detection system, this paper proposes a novel underdetermined wideband DOA estimation method equipped with the nested array (NA) using focused atomic norm minimization (ANM), where the signal source number detection is accomplished by information theory criteria. In the proposed DOA estimation method, especially, after vectoring the covariance matrix of each frequency bin, each corresponding obtained vector is focused into the predefined frequency bin by focused matrix. Then, the collected averaged vector is considered as virtual array model, whose steering vector exhibits the Vandermonde structure in terms of the obtained virtual array geometries. Further, the new covariance matrix is recovered based on ANM by semi-definite programming (SDP), which utilizes the information of the Toeplitz structure. Finally, the Root-MUSIC algorithm is applied to estimate the DOAs. Simulation results show that the proposed method outperforms other underdetermined DOA estimation methods based on information theory in term of higher estimation accuracy. Full article

(This article belongs to the Special Issue Entropy and Information Theory in Acoustics)

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19 pages, 1011 KiB

Open AccessArticle

Application of Spherical-Radial Cubature Bayesian Filtering and Smoothing in Bearings Only Passive Target Tracking

by Wasiq Ali, Yaan Li, Zhe Chen, Muhammad Asif Zahoor Raja, Nauman Ahmed and Xiao Chen

Entropy 2019, 21(11), 1088; https://0-doi-org.brum.beds.ac.uk/10.3390/e21111088 - 07 Nov 2019

Cited by 10 | Viewed by 2698

Abstract

In this paper, an application of spherical radial cubature Bayesian filtering and smoothing algorithms is presented to solve a typical underwater bearings only passive target tracking problem effectively. Generally, passive target tracking problems in the ocean environment are represented with the state-space model having linear system dynamics merged with nonlinear passive measurements, and the system is analyzed with nonlinear filtering algorithms. In the present scheme, an application of spherical radial cubature Bayesian filtering and smoothing is efficiently investigated for accurate state estimation of a far-field moving target in complex ocean environments. The nonlinear model of a Kalman filter based on a Spherical Radial Cubature Kalman Filter (SRCKF) and discrete-time Kalman smoother known as a Spherical Radial Cubature Rauch–Tung–Striebel (SRCRTS) smoother are applied for tracking the semi-curved and curved trajectory of a moving object. The worth of spherical radial cubature Bayesian filtering and smoothing algorithms is validated by comparing with a conventional Unscented Kalman Filter (UKF) and an Unscented Rauch–Tung–Striebel (URTS) smoother. Performance analysis of these techniques is performed for white Gaussian measured noise variations, which is a significant factor in passive target tracking, while the Bearings Only Tracking (BOT) technology is used for modeling of a passive target tracking framework. Simulations based experiments are executed for obtaining least Root Mean Square Error (RMSE) among a true and estimated position of a moving target at every time instant in Cartesian coordinates. Numerical results endorsed the validation of SRCKF and SRCRTS smoothers with better convergence and accuracy rates than that of UKF and URTS for each scenario of passive target tracking problem. Full article

(This article belongs to the Special Issue Entropy and Information Theory in Acoustics)

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13 pages, 4225 KiB

Open AccessArticle

Feature Extraction of Ship-Radiated Noise Based on Intrinsic Time-Scale Decomposition and a Statistical Complexity Measure

by Junxiong Wang and Zhe Chen

Entropy 2019, 21(11), 1079; https://0-doi-org.brum.beds.ac.uk/10.3390/e21111079 - 04 Nov 2019

Cited by 13 | Viewed by 2218

Abstract

Extracting effective features from ship-radiated noise is an important way to improve the detection and recognition performance of passive sonar. Complexity features of ship-radiated noise have attracted increasing amounts of attention. However, the traditional definition of complexity based on entropy (information stored in the system) is not accurate. To this end, a new statistical complexity measure is proposed in this paper based on spectrum entropy and disequilibrium. Since the spectrum features are unique to the class of the ship, our method can distinguish different ships according to their location in the two-dimensional plane composed of complexity and spectrum entropy (CSEP). To weaken the influence of ocean ambient noise, the intrinsic time-scale decomposition (ITD) is applied to preprocess the data in this study. The effectiveness of the proposed method is validated through a classification experiment of four types of marine vessels. The recognition rate of the ITD-CSEP methodology achieved 94%, which is much higher than that of traditional feature extraction methods. Moreover, the ITD-CSEP is fast and parameter free. Hence, the method can be applied in the real time processing practical applications. Full article

(This article belongs to the Special Issue Entropy and Information Theory in Acoustics)

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20 pages, 6172 KiB

Open AccessArticle

Texture Classification Using Spectral Entropy of Acoustic Signal Generated by a Human Echolocator

by Raja Syamsul Azmir Raja Abdullah, Nur Luqman Saleh, Sharifah Mumtazah Syed Abdul Rahman, Nur Syazmira Zamri and Nur Emileen Abdul Rashid

Entropy 2019, 21(10), 963; https://0-doi-org.brum.beds.ac.uk/10.3390/e21100963 - 02 Oct 2019

Cited by 2 | Viewed by 3346

Abstract

Human echolocation is a biological process wherein the human emits a punctuated acoustic signal, and the ear analyzes the echo in order to perceive the surroundings. The peculiar acoustic signal is normally produced by clicking inside the mouth. This paper utilized this unique acoustic signal from a human echolocator as a source of transmitted signal in a synthetic human echolocation technique. Thus, the aim of the paper was to extract information from the echo signal and develop a classification scheme to identify signals reflected from different textures at various distance. The scheme was based on spectral entropy extracted from Mel-scale filtering output in the Mel-frequency cepstrum coefficient of a reflected echo signal. The classification process involved data mining, features extraction, clustering, and classifier validation. The reflected echo signals were obtained via an experimental setup resembling a human echolocation scenario, configured for synthetic data collection. Unlike in typical speech signals, extracted entropy from the formant characteristics was likely not visible for the human mouth-click signals. Instead, multiple peak spectral features derived from the synthesis signal of the mouth-click were assumed as the entropy obtained from the Mel-scale filtering output. To realize the classification process, K-means clustering and K-nearest neighbor processes were employed. Moreover, the impacts of sound propagation toward the extracted spectral entropy used in the classification outcome were also investigated. The outcomes of the classifier performance herein indicated that spectral entropy is essential for human echolocation. Full article

(This article belongs to the Special Issue Entropy and Information Theory in Acoustics)

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20 pages, 1061 KiB

Open AccessArticle

A Comparative Study of Multiscale Sample Entropy and Hierarchical Entropy and Its Application in Feature Extraction for Ship-Radiated Noise

by Weijia Li, Xiaohong Shen and Yaan Li

Entropy 2019, 21(8), 793; https://0-doi-org.brum.beds.ac.uk/10.3390/e21080793 - 14 Aug 2019

Cited by 18 | Viewed by 3356

Abstract

The presence of marine ambient noise makes it difficult to extract effective features from ship-radiated noise. Traditional feature extraction methods based on the Fourier transform or wavelets are limited in such a complex ocean environment. Recently, entropy-based methods have been proven to have many advantages compared with traditional methods. In this paper, we propose a novel feature extraction method for ship-radiated noise based on hierarchical entropy (HE). Compared with the traditional entropy, namely multiscale sample entropy (MSE), which only considers information carried in the lower frequency components, HE takes into account both lower and higher frequency components of signals. We illustrate the different properties of HE and MSE by testing them on simulation signals. The results show that HE has better performance than MSE, especially when the difference in signals is mainly focused on higher frequency components. Furthermore, experiments on real-world data of five types of ship-radiated noise are conducted. A probabilistic neural network is employed to evaluate the performance of the obtained features. Results show that HE has a higher classification accuracy for the five types of ship-radiated noise compared with MSE. This indicates that the HE-based feature extraction method could be used to identify ships in the field of underwater acoustic signal processing. Full article

(This article belongs to the Special Issue Entropy and Information Theory in Acoustics)

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17 pages, 886 KiB

Open AccessArticle

Automatic Modulation Classification of Digital Communication Signals Using SVM Based on Hybrid Features, Cyclostationary, and Information Entropy

by Yangjie Wei, Shiliang Fang and Xiaoyan Wang

Entropy 2019, 21(8), 745; https://0-doi-org.brum.beds.ac.uk/10.3390/e21080745 - 30 Jul 2019

Cited by 19 | Viewed by 3867

Abstract

Since digital communication signals are widely used in radio and underwater acoustic systems, the modulation classification of these signals has become increasingly significant in various military and civilian applications. However, due to the adverse channel transmission characteristics and low signal to noise ratio (SNR), the modulation classification of communication signals is extremely challenging. In this paper, a novel method for automatic modulation classification of digital communication signals using a support vector machine (SVM) based on hybrid features, cyclostationary, and information entropy is proposed. In this proposed method, by combining the theory of the cyclostationary and entropy, based on the existing signal features, we propose three other new features to assist the classification of digital communication signals, which are the maximum value of the normalized cyclic spectrum when the cyclic frequency is not zero, the Shannon entropy of the cyclic spectrum, and Renyi entropy of the cyclic spectrum respectively. Because these new features do not require any prior information and have a strong anti-noise ability, they are very suitable for the identification of communication signals. Finally, a one against one SVM is designed as a classifier. Simulation results show that the proposed method outperforms the existing methods in terms of classification performance and noise tolerance. Full article

(This article belongs to the Special Issue Entropy and Information Theory in Acoustics)

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16 pages, 5521 KiB

Open AccessArticle

Underwater Bearing-Only and Bearing-Doppler Target Tracking Based on Square Root Unscented Kalman Filter

by Xiaohua Li, Chenxu Zhao, Jing Yu and Wei Wei

Entropy 2019, 21(8), 740; https://0-doi-org.brum.beds.ac.uk/10.3390/e21080740 - 28 Jul 2019

Cited by 28 | Viewed by 4137

Abstract

Underwater target tracking system can be kept covert using the bearing-only or the bearing-Doppler measurements (passive measurements), which will reduce the risk of been detected. According to the characteristics of underwater target tracking, the square root unscented Kalman filter (SRUKF) algorithm, which is based on the Bayesian theory, was applied to the underwater bearing-only and bearing-Doppler non-maneuverable target tracking problem. Aiming at the shortcomings of the unscented Kalman filter (UKF), the SRUKF uses the QR decomposition and the Cholesky factor updating, in order to avoid that the process noise covariance matrix loses its positive definiteness during the target tracking period. The SRUKF uses sigma sampling to avoid the linearization of the nonlinear bearing-only and the bearing-Doppler measurements. To ensure the target state observability in underwater target tracking, the paper uses single maneuvering observer to track the single non-maneuverable target. The simulation results show that the SRUKF has better tracking performance than the extended Kalman filter (EKF) and the UKF in tracking accuracy and stability, and the computational complexity of the SRUKF algorithm is low. Full article

(This article belongs to the Special Issue Entropy and Information Theory in Acoustics)

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18 pages, 11215 KiB

Open AccessArticle

A Feature Extraction Method of Ship-Radiated Noise Based on Fluctuation-Based Dispersion Entropy and Intrinsic Time-Scale Decomposition

by Zhaoxi Li, Yaan Li and Kai Zhang

Entropy 2019, 21(7), 693; https://0-doi-org.brum.beds.ac.uk/10.3390/e21070693 - 15 Jul 2019

Cited by 35 | Viewed by 3822

Abstract

To improve the feature extraction of ship-radiated noise in a complex ocean environment, fluctuation-based dispersion entropy is used to extract the features of ten types of ship-radiated noise. Since fluctuation-based dispersion entropy only analyzes the ship-radiated noise signal in single scale and it cannot distinguish different types of ship-radiated noise effectively, a new method of ship-radiated noise feature extraction is proposed based on fluctuation-based dispersion entropy (FDispEn) and intrinsic time-scale decomposition (ITD). Firstly, ten types of ship-radiated noise signals are decomposed into a series of proper rotation components (PRCs) by ITD, and the FDispEn of each PRC is calculated. Then, the correlation between each PRC and the original signal are calculated, and the FDispEn of each PRC is analyzed to select the Max-relative PRC fluctuation-based dispersion entropy as the feature parameter. Finally, by comparing the Max-relative PRC fluctuation-based dispersion entropy of a certain number of the above ten types of ship-radiated noise signals with FDispEn, it is discovered that the Max-relative PRC fluctuation-based dispersion entropy is at the same level for similar ship-radiated noise, but is distinct for different types of ship-radiated noise. The Max-relative PRC fluctuation-based dispersion entropy as the feature vector is sent into the support vector machine (SVM) classifier to classify and recognize ten types of ship-radiated noise. The experimental results demonstrate that the recognition rate of the proposed method reaches 95.8763%. Consequently, the proposed method can effectively achieve the classification of ship-radiated noise. Full article

(This article belongs to the Special Issue Entropy and Information Theory in Acoustics)

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16 pages, 4798 KiB

Open AccessArticle

A New Feature Extraction Method for Ship-Radiated Noise Based on Improved CEEMDAN, Normalized Mutual Information and Multiscale Improved Permutation Entropy

by Zhe Chen, Yaan Li, Renjie Cao, Wasiq Ali, Jing Yu and Hongtao Liang

Entropy 2019, 21(6), 624; https://0-doi-org.brum.beds.ac.uk/10.3390/e21060624 - 25 Jun 2019

Cited by 22 | Viewed by 3815

Abstract

Extracting useful features from ship-radiated noise can improve the performance of passive sonar. The entropy feature is an important supplement to existing technologies for ship classification. However, the existing entropy feature extraction methods for ship-radiated noise are less reliable under noisy conditions because they lack noise reduction procedures or are single-scale based. In order to simultaneously solve these problems, a new feature extraction method is proposed based on improved complementary ensemble empirical mode decomposition with adaptive noise (ICEEMDAN), normalized mutual information (norMI), and multiscale improved permutation entropy (MIPE). Firstly, the ICEEMDAN is utilized to obtain a group of intrinsic mode functions (IMFs) from ship-radiated noise. The noise reduction process is then conducted by identifying and eliminating the noise IMFs. Next, the norMI and MIPE of the signal-dominant IMFs are calculated, respectively; and the norMI is used to weigh the corresponding MIPE result. The multi-scale entropy feature is finally defined as the sum of the weighted MIPE results. Experimental results show that the recognition rate of the proposed method achieves 90.67% and 83%, respectively, under noise free and 5 dB conditions, which is much higher than existing entropy feature extraction algorithms. Hence, the proposed method is more reliable and suitable for feature extraction of ship-radiated noise in practice. Full article

(This article belongs to the Special Issue Entropy and Information Theory in Acoustics)

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17 pages, 3712 KiB

Open AccessArticle

A Novel Linear Spectrum Frequency Feature Extraction Technique for Warship Radio Noise Based on Complete Ensemble Empirical Mode Decomposition with Adaptive Noise, Duffing Chaotic Oscillator, and Weighted-Permutation Entropy

by Yuxing Li, Long Wang, Xueping Li and Xiaohui Yang

Entropy 2019, 21(5), 507; https://0-doi-org.brum.beds.ac.uk/10.3390/e21050507 - 18 May 2019

Cited by 39 | Viewed by 4648

Abstract

Warships play an important role in the modern sea battlefield. Research on the line spectrum features of warship radio noise signals is helpful to realize the classification and recognition of different types of warships, and provides critical information for sea battlefield. In this paper, we proposed a novel linear spectrum frequency feature extraction technique for warship radio noise based on complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN), duffing chaotic oscillator (DCO), and weighted-permutation entropy (W-PE). The proposed linear spectrum frequency feature extraction technique, named CEEMDAN-DCO-W-PE has the following advantages in comparison with other linear spectrum frequency feature extraction techniques; (i) as an adaptive data-driven algorithm, CEEMDAN has more accurate and more reliable decomposition performance than empirical mode decomposition (EMD) and ensemble EMD (EEMD), and there is no need for presetting parameters, such as decomposition level and basis function; (ii) DCO can detect the linear spectrum of narrow band periodical warship signals by way of utilizing its properties of sensitivity for weak periodical signals and the immunity for noise; and (iii) W-PE is used in underwater acoustic signal feature extraction for the first time, and compared with traditional permutation entropy (PE), W-PE increases amplitude information to some extent. Firstly, warship radio noise signals are decomposed into some intrinsic mode functions (IMFs) from high frequency to low frequency by CEEMDAN. Then, DCO is used to detect linear spectrum of low-frequency IMFs. Finally, we can determine the linear spectrum frequency of low-frequency IMFs using W-PE. The experimental results show that the proposed technique can accurately extract the line spectrum frequency of the simulation signals, and has a higher classification and recognition rate than the traditional techniques for real warship radio noise signals. Full article

(This article belongs to the Special Issue Entropy and Information Theory in Acoustics)

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