Location-associated indoor behavior analysis of multiple persons

Recording of the activity of people working in an office or in a living room is important for several goals: to design an evacuation route, to measure the degree of ADL (Activity of Daily Living) of single-living elderly persons, and to analyze the working contents of people, and so on. Camera systems are available for these goals, but they are weak for the light condition change (not available at dark in general) and invasive for the users' privacy. Therefore, we use an infrared ceiling sensor network for localizing moving people and use some extra pieces of evidence for identifying them. Such ID evidence is taken from a finger-vein authentication system at the entrance/exit and from the staying duration at their personal desks. The kind of activity of individuals is determined by the locations and the staying duration related to those activities, e.g., spending two minutes or more at kitchen means “cooking.” A challenging task is to find how to recover missing IDs and related their activities. This sometimes happens when two or more persons cross or meet at a place or someone sits at a desk silently, because a motion sensor reacts only when something with human temperature “moves” in the focus of view. This system succeeded in recording of the activity of three persons for three hours at 87.4% and six persons for seven hours at 15.0%.