MDF-Net: A multi-view dual-attention fusion network for efficient bird sound classification

Bird sound serves as a crucial means of acoustic communication for birds, and its classification research is conducive to the protection, health, and diversity of the ecological ecosystems. Using various feature extraction methods to extract multi-view features can provide more comprehensive information about bird sound, which is a potential method to improve the accuracy of bird sound classification. However, efficiently fusing multi-view features to identify birds accurately remains a challenging task. To address this problem, this paper presents an efficient bird sound classification framework called MDF-Net. The approach extracts four acoustic features from bird sound audios, including wavelet transform spectrogram, Hilbert-Huang transform spectrogram, short-time Fourier transform spectrogram, and Mel-frequency cepstral coefficients, to fully describe the characteristics of bird sound from different views. Subsequently, convolutional neural network is used as advanced feature extractor to obtain deep features of these spectrograms. Then, the multi-head self-attention mechanism focuses on the correlation and importance of different features in each view to obtain essential and expressive feature representations. And the cross-attention mechanism is employed to align and correlate information in the four views, which makes it easier for the classifier to understand the relationships between features of different views. Finally, combined with the results of the dual-attention mechanism, a multi-view fusion feature with difference and diversity is constructed, and it applied to the bird sound classification. In this study, audios from16 bird species constitute the dataset. The multi-view fusion feature based on MDF-Net achieved a classification accuracy of 97.29%, outperformed the 9 single features and 3 fused features used in the experiments. The result demonstrate that the proposed MDF-Net successfully captures the feature relationships within single-view and between multi-view, providing crucial information for correctly classifying bird sound samples. The approach efficiently fuses the features of different views and improves the performance of bird sound classification.