Spy camera hides friendly faces

'Privacy block' may save your blushes but faces can be revealed if neceesary for investigations

A new kind of CCTV camera that promises less invasive surveillance is being trialled in the US.

Developed by computer scientists at the University of California, Berkeley, the CCTV camera can obscure a person's face with an oval spot.

The so-called 'respectful camera' is designed for use in day-to-day surveillance and the oval spots can be removed by authorities in the event of an investigation.

The UK currently leads the world in the use of CCTV cameras, according to stats from the Information Commissioner's Office. There are currently 4.2 million surveillance cameras dotted around the country, a ratio of one camera for every 14 people.

The respectful camera works with a special marker vest, worn by test subjects. Tested on a building site, the camera identified workers wearing the markers 93 per cent of the time, and blocked their faces.

In environments with more controlled lighting, that detection figure rose to 96 per cent. The developers picture the vest becoming little more than a button-sized tag in the future that people could easily wear.

"Cameras are here to stay, and there's no avoiding it," UC Berkeley computer scientist Ken Goldberg told the MIT Technology Review . "Let's figure out new technology to make them less invasive."