An elderly man wakes up at dawn in his small studio apartment, where he stays alone. He lights the stove to make a pot of tea, switches on the toaster oven, and takes some bread and jelly from the cupboard. After taking his morning medication, a computer-generated voice gently reminds him to turn off the toaster. Later that day, his daughter accesses a secure website where she scans a check-list, which was created by a sensor network in her father’s apartment. She finds that her father is eating normally, taking his medicine on schedule, and continuing to manage his daily life on his own. Thanks to progresses in activity recognition (AR), that information puts her mind at ease.

Activity recognition is the science of  recognizing the actions, interactions and goals of one or more agents from a series of observations on the agents’ actions and the environmental conditions. This field is a wide area of research, it covers branches like Object Detection and Tracking (ODT), Activity Recognition (AR), Ambient intelligence (AmI) and so on.