Software which links ordinary mobile phones into a smart camera surveillance network has been developed by Swiss researchers.

The software, named Facet, was conceived at the Institute of Pervasive Computing in Zurich by three researchers: Phillip Bolliger, Moritz Köhler and Kay Römer.

According to the researchers' academic paper Facet: Towards a Smart Camera Network of Mobile Phones, previous research in the area of mobile surveillance has focused on custom hardware solutions. Their solution, however, relies on software to link ordinary mobile phones into a mesh-like network.

"Because of the way we implemented it, the whole thing will run in Java on virtually any phone you want," Bolliger told New Scientist Tech.

According to the academic paper, each mobile phone captures a stream of images from its camera and analyses them to see objects entering and exiting its field of view -- creating a surveillance network and relaying the details back to the interested party over a cellular connection, such as GPRS.

The ad hoc network is formed when phones patch with other mobile devices nearby, using short-range communication such as Bluetooth. When a phone witnesses an object entering or exiting its vision, it broadcasts this event to all the phones in the surveillance network.

By using the average speed of a walking person, taken as 1.5 m/s, the phones are able to estimate their distance away from each other, noting the times when an object or person leaves one phone's view and enters another. As a result, the scope of the network is determined.

With this completed, the system can undertake complicated tasks, such as monitoring a hallway, or guarding a campsite, Bolliger told New Scientist Tech.

The paper has, however, outlined some problems with the system, including the time delay in sending Bluetooth messages. The delay means that the system is not able to keep up with fast-moving objects, limiting the network's surveillance potential.

The researchers said in their paper they hope to publish the Facet software as an open source project, in order to encourage community-driven development on smart camera networks.

The open source software could be of help to more than just casual users. According to USA Today, the Department of Homeland Security is looking into outfitting mobile phones with sensors that could detect radioactive isotopes, toxic chemicals or biological weapons such as anthrax.