Respiratory Disease Classification Using NMF-Enhanced Log-Mel Spectrograms and Convolutional Recurrent Neural
Bowen Han1, Wei Quan1, Bogdan Matuszewski1
1School of Engineering and Computing, University of Lancashire, Preston PR1 2HE, UK.
Sensors (Basel, Switzerland)
|July 15, 2026
Summary
This study introduces a new method for classifying respiratory diseases using lung sounds. The NMF-enhanced deep learning model accurately identifies conditions like Asthma, COPD, and Pneumonia from audio recordings.
Area of Science:
- Medical acoustics
- Artificial intelligence in healthcare
- Signal processing for biomedical applications
Background:
- Respiratory disease classification from lung sounds is difficult due to signal noise and overlapping acoustic patterns.
- Existing methods struggle with the heterogeneity of audio data and diverse disease presentations.
Purpose of the Study:
- To develop and evaluate a novel framework for multi-class respiratory disease classification using enhanced lung sound analysis.
- To improve the accuracy and robustness of automated detection for conditions including Asthma, COPD, Pneumonia, and others.
Main Methods:
- Lung sound recordings from public datasets were harmonized into a unified seven-class label space.
- A Non-negative Matrix Factorization (NMF) enhancement was applied to log-mel spectrograms for improved feature salience.
- A Convolutional Recurrent Neural Network (CRNN) with attention was developed and compared against other deep learning architectures.
Main Results:
- The proposed CRNN model achieved high performance, with 96.14% accuracy and 94.05% Macro-F1 score on the seven-class dataset.
- The CRNN demonstrated superior class separation and more balanced recognition across different respiratory diseases compared to RDLINet, ResNet, and YOLO-style models.
- Class-wise analysis and confusion matrix evaluation confirmed the CRNN's effectiveness.
Conclusions:
- NMF-enhanced spectro-temporal modeling combined with CRNNs offers a powerful approach for automated multi-class respiratory disease classification.
- This framework shows significant potential for clinical applications in diagnosing respiratory conditions from lung sound recordings.
- The study highlights the benefits of advanced signal processing and deep learning for overcoming challenges in respiratory sound analysis.
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