Nonintrusive Monitoring and Detection of Sitting and Lying Persons: A Technological Review

The detection and monitoring of a sitting or lying person using non-intrusive sensing technologies can contribute to a wide range of applications aimed at improving quality of life, such as human activity recognition, sleep quality assessment, and the detection of behavioural abnormalities. This systematic review provides a comprehensive overview of non-intrusive sensing technologies for detecting sitting and lying individuals, including those capable of monitoring vital signs. The article offers a detailed classification of these technologies based on the physical variables they measure, providing a concise understanding of the principles behind each technology, along with an analysis of their respective pros and cons. For each technology, this review provides an overview of the most significant recent works (of 552 analyzed, 90 were selected) that demonstrate their applications and purposes. The spectrum of sensors analyzed includes mechanical, electrical, optical, acoustic, magnetic, and thermal sensors, each evaluated for its strengths, limitations, and potential uses, showing recent trends.