Automatic Detection and Unsupervised Clustering-Based Classification of Cetacean Vocal Signals

In the ocean environment, passive acoustic monitoring (PAM) is an important technique for the surveillance of cetacean species. Manual detection for a large amount of PAM data is inefficient and time-consuming. To extract useful features from a large amount of PAM data for classifying different ceta...

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Main Authors: Yinian Liang, Yan Wang, Fangjiong Chen, Hua Yu, Fei Ji, Yankun Chen
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/15/7/3585
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author Yinian Liang
Yan Wang
Fangjiong Chen
Hua Yu
Fei Ji
Yankun Chen
author_facet Yinian Liang
Yan Wang
Fangjiong Chen
Hua Yu
Fei Ji
Yankun Chen
author_sort Yinian Liang
collection DOAJ
description In the ocean environment, passive acoustic monitoring (PAM) is an important technique for the surveillance of cetacean species. Manual detection for a large amount of PAM data is inefficient and time-consuming. To extract useful features from a large amount of PAM data for classifying different cetacean species, we propose an automatic detection and unsupervised clustering-based classification method for cetacean vocal signals. This paper overcomes the limitations of the traditional threshold-based method, and the threshold is set adaptively according to the mean value of the signal energy in each frame. Furthermore, we also address the problem of the high cost of data training and labeling in deep-learning-based methods by using the unsupervised clustering-based classification method. Firstly, the automatic detection method extracts vocal signals from PAM data and, at the same time, removes clutter information. Then, the vocal signals are analyzed for classification using a clustering algorithm. This method grabs the acoustic characteristics of vocal signals and distinguishes them from environmental noise. We process 194 audio files in a total of 25.3 h of vocal signal from two marine mammal public databases. Five kinds of vocal signals from different cetaceans are extracted and assembled to form 8 datasets for classification. The verification experiments were conducted on four clustering algorithms based on two performance metrics. The experimental results confirm the effectiveness of the proposed method. The proposed method automatically removes about 75% of clutter data from 1581.3MB of data in audio files and extracts 75.75 MB of the features detected by our algorithm. Four classical unsupervised clustering algorithms are performed on the datasets we made for verification and obtain an average accuracy rate of 84.83%.
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spelling doaj-art-bf1b3085b14a4e5ca7ad3d8e34888f372025-08-20T02:09:13ZengMDPI AGApplied Sciences2076-34172025-03-01157358510.3390/app15073585Automatic Detection and Unsupervised Clustering-Based Classification of Cetacean Vocal SignalsYinian Liang0Yan Wang1Fangjiong Chen2Hua Yu3Fei Ji4Yankun Chen5School of Electronic and Information Engineering, South China University of Technology, Guangzhou 510640, ChinaSchool of Computer Science and Engineering, South China University of Technology, Guangzhou 510640, ChinaSchool of Electronic and Information Engineering, South China University of Technology, Guangzhou 510640, ChinaSchool of Electronic and Information Engineering, South China University of Technology, Guangzhou 510640, ChinaSchool of Electronic and Information Engineering, South China University of Technology, Guangzhou 510640, ChinaKey Laboratory of Marine Environmental Survey Technology and Application, South China Sea Marine Survey and Technology Center of State Oceanic Administration (SMST), Ministry of Natural Resources, Guangzhou 510300, ChinaIn the ocean environment, passive acoustic monitoring (PAM) is an important technique for the surveillance of cetacean species. Manual detection for a large amount of PAM data is inefficient and time-consuming. To extract useful features from a large amount of PAM data for classifying different cetacean species, we propose an automatic detection and unsupervised clustering-based classification method for cetacean vocal signals. This paper overcomes the limitations of the traditional threshold-based method, and the threshold is set adaptively according to the mean value of the signal energy in each frame. Furthermore, we also address the problem of the high cost of data training and labeling in deep-learning-based methods by using the unsupervised clustering-based classification method. Firstly, the automatic detection method extracts vocal signals from PAM data and, at the same time, removes clutter information. Then, the vocal signals are analyzed for classification using a clustering algorithm. This method grabs the acoustic characteristics of vocal signals and distinguishes them from environmental noise. We process 194 audio files in a total of 25.3 h of vocal signal from two marine mammal public databases. Five kinds of vocal signals from different cetaceans are extracted and assembled to form 8 datasets for classification. The verification experiments were conducted on four clustering algorithms based on two performance metrics. The experimental results confirm the effectiveness of the proposed method. The proposed method automatically removes about 75% of clutter data from 1581.3MB of data in audio files and extracts 75.75 MB of the features detected by our algorithm. Four classical unsupervised clustering algorithms are performed on the datasets we made for verification and obtain an average accuracy rate of 84.83%.https://www.mdpi.com/2076-3417/15/7/3585passive acoustic monitoringempirical mode decompositionendpoint detectionunsupervised clusteringmarine mammal vocal signals
spellingShingle Yinian Liang
Yan Wang
Fangjiong Chen
Hua Yu
Fei Ji
Yankun Chen
Automatic Detection and Unsupervised Clustering-Based Classification of Cetacean Vocal Signals
Applied Sciences
passive acoustic monitoring
empirical mode decomposition
endpoint detection
unsupervised clustering
marine mammal vocal signals
title Automatic Detection and Unsupervised Clustering-Based Classification of Cetacean Vocal Signals
title_full Automatic Detection and Unsupervised Clustering-Based Classification of Cetacean Vocal Signals
title_fullStr Automatic Detection and Unsupervised Clustering-Based Classification of Cetacean Vocal Signals
title_full_unstemmed Automatic Detection and Unsupervised Clustering-Based Classification of Cetacean Vocal Signals
title_short Automatic Detection and Unsupervised Clustering-Based Classification of Cetacean Vocal Signals
title_sort automatic detection and unsupervised clustering based classification of cetacean vocal signals
topic passive acoustic monitoring
empirical mode decomposition
endpoint detection
unsupervised clustering
marine mammal vocal signals
url https://www.mdpi.com/2076-3417/15/7/3585
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