Subject Invariant Contrastive Learning for Human Activity Recognition

Fuente: arXiv
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Hauptverfasser: Yarici, Yavuz, Kokilepersaud, Kiran, Prabhushankar, Mohit, AlRegib, Ghassan
Format: Preprint
Veröffentlicht: 2025
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author Yarici, Yavuz
Kokilepersaud, Kiran
Prabhushankar, Mohit
AlRegib, Ghassan
author_facet Yarici, Yavuz
Kokilepersaud, Kiran
Prabhushankar, Mohit
AlRegib, Ghassan
contents The high cost of annotating data makes self-supervised approaches, such as contrastive learning methods, appealing for Human Activity Recognition (HAR). Effective contrastive learning relies on selecting informative positive and negative samples. However, HAR sensor signals are subject to significant domain shifts caused by subject variability. These domain shifts hinder model generalization to unseen subjects by embedding subject-specific variations rather than activity-specific features. As a result, human activity recognition models trained with contrastive learning often struggle to generalize to new subjects. We introduce Subject-Invariant Contrastive Learning (SICL), a simple yet effective loss function to improve generalization in human activity recognition. SICL re-weights negative pairs drawn from the same subject to suppress subject-specific cues and emphasize activity-specific information. We evaluate our loss function on three public benchmarks: UTD-MHAD, MMAct, and DARai. We show that SICL improves performance by up to 11% over traditional contrastive learning methods. Additionally, we demonstrate the adaptability of our loss function across various settings, including multiple self-supervised methods, multimodal scenarios, and supervised learning frameworks.
format Preprint
id arxiv_https___arxiv_org_abs_2507_03250
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Subject Invariant Contrastive Learning for Human Activity Recognition
Yarici, Yavuz
Kokilepersaud, Kiran
Prabhushankar, Mohit
AlRegib, Ghassan
Computer Vision and Pattern Recognition
Machine Learning
The high cost of annotating data makes self-supervised approaches, such as contrastive learning methods, appealing for Human Activity Recognition (HAR). Effective contrastive learning relies on selecting informative positive and negative samples. However, HAR sensor signals are subject to significant domain shifts caused by subject variability. These domain shifts hinder model generalization to unseen subjects by embedding subject-specific variations rather than activity-specific features. As a result, human activity recognition models trained with contrastive learning often struggle to generalize to new subjects. We introduce Subject-Invariant Contrastive Learning (SICL), a simple yet effective loss function to improve generalization in human activity recognition. SICL re-weights negative pairs drawn from the same subject to suppress subject-specific cues and emphasize activity-specific information. We evaluate our loss function on three public benchmarks: UTD-MHAD, MMAct, and DARai. We show that SICL improves performance by up to 11% over traditional contrastive learning methods. Additionally, we demonstrate the adaptability of our loss function across various settings, including multiple self-supervised methods, multimodal scenarios, and supervised learning frameworks.
title Subject Invariant Contrastive Learning for Human Activity Recognition
topic Computer Vision and Pattern Recognition
Machine Learning
url https://arxiv.org/abs/2507.03250