A new microphone system allows broadcasters to zoom in on sounds as well as sights, to pick out a single conversation to eavesdrop on conversations between suspicious people.

Physicists Morgan Kjølerbakken and Vibeke Jahr, formerly at the University of Oslo, Norway, were working on sonar technology when they came up with the idea for what they call a supermicrophone, now dubbed the AudioScope, the New Scientist said in a report.

The device is made up of around 300 microphones arranged in a fixed circular array above the sports ground. They are used in conjunction with a wide-angle camera that can zoom in to any position on the pitch. Because the camera is also fixed, it can be calibrated to zoom in to any location within its range, it further noted.

The AudioScope software then calculates the time it would take for sound emanating from that point to reach each microphone in the circular array, and digitally corrects each audio feed to synchronise them with that spot, the report said.

If we correct the audio arriving at three microphones then we have a signal that is three times as strong, Kjølerbakken was quoted as saying.

 Kjølerbakken and Jahr have now patented the device and founded a company - Squarehead Technology - to develop their idea.