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Facing up to CCTV

A closed-circuit television (CCTV) security surveillance camera that proves irresistible to look at, guaranteeing a full-face image of the passer-by, is based on research by Professor Deborah Withington of Leeds University in northern England.

The CCTV system, being manufactured by Sound Alert, works by emitting a broadband noise that is triggered when someone passes by. Broadband noise comprises a simultaneous range of frequencies which provides the brain with enough information to pinpoint the direction from where the sound is coming.

The part of the brain that reacts to broadband noise - a reaction which humans share with most other animals - is called the superior colliculus. As soon as this is alerted it instinctively locates the precise source and triggers a physical movement towards it.

Broadband noises occur frequently in nature, for example a snapping twig or rustling leaves. They are sounds that animals need to pinpoint in order to avoid predators. Broadband noises key in to our survival instincts.

Tests done with narrowband sound did not generate full-face images because the brain cannot gather enough information from the small range of frequencies to locate the source and people either ignore the sound or look in another direction. Professor Withington discovered that people about to commit a crime are agitated and anxious. She demonstrated in tests that these people are even more susceptible to responding to broadband noise because they are on the alert for just that type of sound.

Sound Alert, which now owns the intellectual property rights to the idea, specialises in identifying sound patterns which are already being used in a number of products to improve safety, security and communications in industry.

For further details contact Sound Alert, tel: (0944) 1372 456037, e-mail: [email protected]

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