ORIGINAL RESEARCH article
Front. Comput. Sci.
Sec. Mobile and Ubiquitous Computing
Assisting Annotators of Wearable Activity Recognition Datasets through Automated Sensor-based Suggestions
Provisionally accepted
- University of Sussex, Brighton, United Kingdom
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Wearable Activity Recognition consists of recognising actions of people from on-body sensor data using machine learning. Developing suitable machine learning models typically requires substantial amounts of annotated training data. Manually annotating large datasets is tedious and time intensive. Interactive machine learning systems can be used to support this, with the aim of reducing annotation time or improving accuracy. We contribute a new web-based annotation tool for time series signals synchronised with a video recording with integrated automated suggestions, facilitated by ML models, to assist and improve the annotation process of annotators. This is enabled by focusing user attention towards points of interest. This is particularly relevant for the annotation of long periodic activities to allow fast navigation in large datasets without skipping start and end points of activities. To evaluate the efficacy of this system, we conducted a user study with 32 participants who were tasked with annotating modes of locomotion in a dataset composed of multiple long (over 12 hours) consecutive sensor recordings captured by body-worn accelerometers. We analysed the quantitative impact on annotation performance and the qualitative impact on the user experience. The results show that the implemented annotation assistance improved the annotation quality by 11% F1 Score but reduced annotation speed by 20%, whereas the NASA Task Load Index results show that participants perceived the assistance as beneficial for annotation speed but not for annotation quality.
Keywords: Human activity recognition, data annotation, statistical change detection, human-computer interaction, wearablecomputing, deep learning, attention mechanism, human factors
Received: 31 Aug 2025; Accepted: 16 Oct 2025.
Copyright: © 2025 Gunthermann, Simpson, Birch and Roggen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Lukas Gunthermann, lukasgue@gmail.com
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