Boffins in Ohio have taken another step towards the global surveillance panopticon of the future, developing software which can autonomously track an individual through a city using CCTV cameras.

James W Davis, associate prof at the Ohio State computer science and engineering department, developed the new spyware with the aid of grad student Karthik Sankaranarayanan.

Davis and Sankaranarayanan's code works by using a pan-tilt-zoom camera to create a panoramic image of its entire field of view, and then linking each ground pixel in the picture to a georeferenced location on a map. This means that when the camera sees a person or vehicle, the computer also knows in terms of map coordinates where it is looking.

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That in turn makes it possible for a new camera to be trained on the target as he/she/it passes out of the first one's field of view. In this way, a subject can be followed automatically anywhere that the monitoring computer has CCTV coverage. There's no need for a human operator to manually train cameras around, using up man-hours and sooner or later making a mistake and losing track.

"That's the advantage of linking all the cameras together in one system - you could follow a person's trajectory seamlessly," says Davis.

For now, such camera networks are small and localised. However, the Home Office here in the UK has said it would like to "create an effective cross country strategic CCTV network". Such a network, combined with Davis and Sankaranarayanan's new software, would allow plods or spooks to track people completely hands-off. That said, until facial-recognition software gets a lot better the computers would lose their target as soon as he or she left CCTV coverage.

Not content with his efforts so far, Davis wants to go even further and write code which can pick out people "engaging in nefarious behaviour".

"We are trying to automatically learn what typical activity patterns exist in the monitored area, and then have the system look for atypical patterns that may signal a person of interest," he says.

Such systems are already being trialled, and are known to be more than a bit flaky. The panoramic-map software with its people-tracking abilities seems more promising - from a surveillance operator's point of view, anyway.