Supervised Contrastive Learning for Respiratory Sound Classification

Automatic respiratory sound classification using machine learning is a challenging task, due to large biological variability, imbalanced datasets, as well as a diversity in recording techniques used to capture the respiration signal. While datasets with annotated respiration cycles have been proposed, methods based on supervised learning using annotations only may be limited in their generalization capability. In this study, we address this issue using supervised contrastive learning, relying both on respiration cycle annotations and a spectrogram frequency and temporal masking method SpecAugment to generate augmented samples for representation learning with a contrastive loss. We demonstrate that such an approach can outperform supervised learning using experiments on a convolutional neural network trained from scratch, achieving the new state of the art. Our work shows the potential of supervised contrastive learning in imbalanced and noisy settings. Our code is released at https://github.com/ilyassmoummad/scl_icbhi2017