TRLS: A Time Series Representation Learning Framework via Spectrogram for Medical Signal Processing
This work addresses the challenge of extracting robust representations for medical signal processing, which is incremental as it builds on existing methods by incorporating spectrograms and avoiding negative sample design.
The paper tackles the problem of poor generalization in representation learning for unlabeled medical time series by proposing TRLS, a framework that uses spectrograms and a time-frequency encoder with data augmentations, achieving superior classification performance on four real-world datasets.
Representation learning frameworks in unlabeled time series have been proposed for medical signal processing. Despite the numerous excellent progresses have been made in previous works, we observe the representation extracted for the time series still does not generalize well. In this paper, we present a Time series (medical signal) Representation Learning framework via Spectrogram (TRLS) to get more informative representations. We transform the input time-domain medical signals into spectrograms and design a time-frequency encoder named Time Frequency RNN (TFRNN) to capture more robust multi-scale representations from the augmented spectrograms. Our TRLS takes spectrogram as input with two types of different data augmentations and maximizes the similarity between positive ones, which effectively circumvents the problem of designing negative samples. Our evaluation of four real-world medical signal datasets focusing on medical signal classification shows that TRLS is superior to the existing frameworks.