Paint-based graffiti can usually be removed relatively easily from buildings, bus shelters and other street furniture. But graffiti that is scratched into surfaces such as Perspex is much more difficult to cope with and usually requires the entire surface to be replaced at great cost.
So researchers at Curtin University of Technology in Perth, Australia, have developed a device that can hear when graffiti is being carved into surfaces. A set of microphones attached to the surface is connected to a computer program that has been trained to distinguish background noise from the tell-tale signature of graffiti scratches. When the computer picks up signs of vandalism in action, it triggers an alarm to scare off the perpetrators and call the authorities to investigate.
Innovation & Technology Weekly of September 15, 2008 Maastricht Economic and social Research and training centre on Innovation and Technology (UNU-MERIT) European Centre for Digital Communication (EC/DC)
New Scientist – September 10, 2008