In this study, we try to develop a monitoring system that takes into account privacy issues. The monitoring system uses a living area and controls the degree of watching over and privacy protection by changing the granularity of the living area. The living area is defined a set of home, frequently visited place of stay, and travel route connecting them. We proposed an algorithm to generate the living area using GPS data collected for a long period. Experimental results show that the proposed algorithm can estimate living area with a precision of 0.85.
We also carried out questionnaire on user preferences in terms of the monitoring and privacy protection levels used these living area. Experiment results showed that the people on the monitoring side wanted the monitoring system to allow them to monitor in detail. Conversely, it was observed for the people being monitored that the more detailed the monitoring, the greater the feelings of being surveilled intrusively.