Sensors, vision and networks: From video surveillance to activity recognition and health monitoring

This paper presents an overview of the state of the art of three different fields with the shared characteristics of making use of a network of sensors, with the possible application of computer vision, signal processing, and machine learning algorithms. Namely, the paper first reports the state of the art and possible future directions for Intelligent Video Surveillance (IVS) applications, by recaping the history of the field in terms of hardware and algorithmic progresses. Then, the existing technologies of Wireless Sensor Networks (WSNs) are compared and described. Their applications to human activity recognition (HAR), both from a single or multiple sensors perspectives, are described and classified, followed by the current research trends and challenges. Finally, recent advances on camera-based health monitoring (including vision-based Ambient Assisted Living and patient monitoring, and camera-based physiological measurements) are described in full details, with the challenges faced.