Comparative Analysis of Two Methods in Fine-Grained Activity Recognition for Ambient Assisted Living

Abstract The swift progression of artificial intelligence, along with the rising demand for in-home assistance for individuals facing a loss of autonomy, has driven a significant increase in research within the domain of ambient assisted living (AAL). A key challenge challenge in developing assistive technologies in an AAL context concerns the automatic recognition of the ongoing user’s activity. Most existing approaches of Human Activity Recognition (HAR) use a level of abstraction (low granularity) that is insufficient for developing efficient assistive technologies. The majority of them focus primarily on identifying broad categories of activities, such as eating or sleeping. While this identification is sufficient for monitoring general behavior, it does not enable providing practically meaningful real-time, actionable assistance. In this paper, we propose a comparative study of two novel algorithmic approaches for hand gesture recognition, intended to serve as core components of a fine-grained activity recognition model. To this end, we have defined thirteen atomic hand gestures commonly used in cooking activities. The first model we introduce utilizes inertial data, collected from a standard wristband equipped with a triaxial accelerometer and gyroscope, and applies machine learning techniques for analysis. The second model is based on a less conventional approach, employing photoplethysmography (PPG) sensors, which are rarely used for activity recognition. We detail the design and implementation of both approaches and the conducted experiments. Finally, we present a comparative analysis of the obtained results showing the potential of such approaches for the AAL.