In this work, we present an ensemble for automated audio classification that fuses different types of features extracted from audio files. These features are evaluated, compared, and fused with the goal of producing better classification accuracy than other state-of-the-art approaches without ad hoc parameter optimization. We present an ensemble of classifiers that performs competitively on different types of animal audio datasets using the same set of classifiers and parameter settings. To produce this general-purpose ensemble, we ran a large number of experiments that fine-tuned pretrained convolutional neural networks (CNNs) for different audio classification tasks (bird, bat, and whale audio datasets). Six different CNNs were tested, compared, and combined. Moreover, a further CNN, trained from scratch, was tested and combined with the fine-tuned CNNs. To the best of our knowledge, this is the largest study on CNNs in animal audio classification. Our results show that several CNNs can be fine-tuned and fused for robust and generalizable audio classification. Finally, the ensemble of CNNs is combined with handcrafted texture descriptors obtained from spectrograms for further improvement of performance. The MATLAB code used in our experiments will be provided to other researchers for future comparisons at https://github.com/LorisNanni.
Information Technology and Cybersecurity
© 2020 the Authors. 2020 This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original authors and the source, provide a link to the Creative Commons licence, and indicate if changes were made.
Audio classification, Deep learning, Ensemble of classifiers, Handcrafted features, Pattern recognition, Texture
Nanni, Loris; Costa, Yandre M.G.; Aguiar, Rafael L.; Mangolin, Rafael B.; Brahnam, Sheryl; and Silla, Carlos N., "Ensemble of convolutional neural networks to improve animal audio classification" (2020). Articles by College of Business Faculty. 533.
Eurasip Journal on Audio, Speech, and Music Processing