Auditory Map Orients by Sound

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May 15, 2007 — Before venturing out into an unfamiliar area, most people scope out a map. But for the blind or visually impaired, using a map to get oriented is not an option.

An interactive computer program in development could change that. It paints a picture of a city, not with images, but with sounds. Not only could the technology aide the visually impaired by giving them a sense of place before they explore the unknown, it could also offer sighted people audio cues when in "blind" situations.

"A firefighter could get a signal through a helmet headset as soon as he is losing track inside a dangerous building or if he needs to be directed to a doorway or a victim," said professor Susanne Boll of the University of Oldenburg in Germany.

The interactive map allows a person to explore a city either from a bird's eye perspective or by walking through a virtual, three-dimensional environment. The traveler explores the city by moving a stylus across a tablet PC. The stylus and the edges of the PC help the person feel the extent of the map and develop a mental model of the space.

Geographic features such as buildings, parks, lakes and tourist sites are represented by corresponding sounds. For example, a park sounds like singing birds, lakes sound like dabbling water and sightseeing spots sound like camera shutter clicks.

"There is no other project that really does a transfer from a visual map with its geographical relations and distances into a non-speech sound environment," said Boll.

Because hearing all objects at once could cause a lot of confusion, the map comes with an auditory torch, which the person can use to acoustically illuminate large or small areas one at a time. Only features falling under the glow of the torch will make noise as the traveler moves the torch around. And nearby objects sound louder than those farther away.

Ben Shneiderman of the University of Maryland, College Park, calls the interactive map "an inspirational prototype."

"It works fine for small examples and it's a promising direction," he said.

However, Shneiderman added that while it's important to make the sounds unique, that means there is a limit to how many can be incorporated into the map.

"If sounds are distinctive enough it helps, but once you start having too many different sounds, it takes you a while to figure out what's going on," said Shneiderman.

Boll and her team want to eventually pair the interactive map with tactile technology that would help the person navigate actual city streets.

Let's say the person has learned the map at home and wants to walk to the park. She would download information to a vibrating belt and wear the belt on her journey. Different sides of the belt would vibrate to cue her to turn left or right, guiding her to the ultimate destination.