SYDNEY, 15 August 2006: Blind people may one day ditch their white sticks for a pair of high-tech sunglasses and shoes, according to Hong Kong scientists.

The researchers, from the Hong Kong Polytechnic University, said they have developed a sound-emitting device that can be built into sunglasses and shoes. The invention uses a computer to interpret the rebounding sound to help the blind detect objects in close proximity.

"Ultrasonic waves are sent out and when they bounce back they are interpreted by a receiver," Wallace Leung Woon-fong, director of the Research Institute of Innovative Products and Technologies told Hong Kong's English-language newspaper, the Sunday Morning Post.

Using only this technique - similar to the echolocation used by bats and dolphins - the device can identify an object's shape, size and texture. The shoes send a vibrating warning signal back to the person if there is something in the way, the researchers said.

"Once an obstacle is detected the shoe will vibrate, perhaps increasing in intensity as the obstacle gets closer," Woon-fong said. "The shoe will be able to detect steps, holes in the road and obstacles within a five-centimetre vertical distance."

The researchers designed the sunglasses based on an existing 'electronic bat ears' technology, a navigational device developed by He Jufang, also at the Hong Kong Polytechnic University.

Many bats have poor eyesight and must rely on sounds to find their way. They emit sound waves from their mouths and interpret the echo created when the sound hits surrounding objects.

Blind people have also been known to translate sounds they hear into accurate mental images of their surroundings, reporting imagining the size and location of objects even the size of a bug.

Another built-in feature in the shoes permits the blind to know their exact location, providing them with an alternative from having to ask random pedestrians for directions. The shoes are equipped a Global Positioning System (GPS), a satellite navigation system, which can provide more accurate information on location.

But some blind people are not as excited about the invention as the scientists might have hoped.

"There are so many bumps in Hong Kong's road. If I wear the shoes I will end up shaking and vibrating all day," Chow Wing-Cheung told the Sunday Morning Post.