Surveillance systems have always seemed like something out of a James Bond movie to me - a system that observes events without being intrusive but is able to capture valuable data that allows people to save the world from sure catastrophe (like the time I forgot to open the flue for the fireplace and almost
burned smoked out the house)! Surveillance systems are used to monitor or observe the behavior of persons, processes, places, objects, etc. to determine whether they are functioning normally or if there is any deviation from their standard behavior.
It is this concept and its integration with wireless sensor networks that researchers at National Chiao Tung University are addressing to develop their iMouse platform, an integrated mobile surveillance and wireless sensor system. Incorporating the environment-sensing capability of wireless sensor networks into video based surveillance systems provides advanced services at a lower cost than traditional systems. The iMouse's integrated mobile surveillance and easy to deploy wireless sensor system uses static and mobile wireless sensors to detect and then analyze unusual events in the environment. Wireless sensor networks (WSN) provide an inexpensive and convenient way to monitor physical environments. The iMouse system, consists of a large number of inexpensive static sensors and a small number of more expensive mobile sensors. The former is to monitor the environment, while the latter can move to certain locations and gather more advanced data. The iMouse system is a mobile, context-aware surveillance system.
The three main components of the iMouse system architecture are (1) the static sensors, (2) the mobile sensors and (3) an external server. The system is set up so that the user could issue commands to the network through the server at which point the static sensors would monitor the environment and report events. When notified of an unusual event or change in behavior, the server notifies the user and dispatches the mobile sensors to move to the emergency sites, collect data and report back to the server.
Each static sensor is equipped with Crossbow's MICAz Motes, available in our WSN-START and WSN-PRO development kits, and a sensor board.The static sensors are placed in known locations which can be established through manual setting, GPS or localization schemes. The static sensors can then determine which sensory input is higher or lower than the predefined threshold. For example, a sensor can interpret a combination of light and temperature readings as a potential fire emergency. To detect an explosion, a sensor can use a combination of temperature and sound readings. Or, for home security, it can use unusual sound or light readings. The mobile sensors consist of Crossbow's Stargate Platform, a Lego car, a MICAz Mote, a webcam and IEEE 802.11 WLAN card to support high-speed, long-distance communications such as transmitting images. These mobile sensors can move to event locations, exchange messages with the other sensors, take snapshots of event scenes and transmit the images. The Stargate controls the movement of the Lego car and the webcam while the MICAz Mote is used to communicate with the static sensor nodes.The external server provides an interface to obtain system status and issue commands.It also maintains the network and interprets the sensor data. The researchers at National Chiao Tung University have developed the dispatch algorithms and user interface to establish the system operation and control flow.
The iMouse system integrates mobile WSN technologies into surveillance technologies to support intelligent mobile surveillance services. This is made possible by the easy to deploy capability of the Mote platform and its flexibility to be integrated into various applications. It is this type of research that is paving the way for future technologies to provide us with more accurate and detailed data about the environments and processes that surround us.