This wearable system, designed by a team at the Georgia Institute of Technology , can guide people with or without vision through a difficult terrain. Featuring integrated robotics, the system uses auditory signals via bone-conduction headphones, and is designed not only for the blind but also for firefighters, soldiers, EMTs and others.
The current SWAN prototype consists of a small laptop computer worn in a backpack, a tracking chip, additional sensors including GPS (global positioning system), a digital compass, a head tracker, four cameras and light sensor, and special headphones called bone phones. The researchers selected bone phones because they send auditory signals via vibrations through the skull without plugging the user’s ears, an especially important feature for the blind who rely heavily on their hearing. The sensors and tracking chip worn on the head send data to the SWAN applications on the laptop which computes the user’s location and in what direction he is looking, maps the travel route, then sends 3-D audio cues to the bone phones to guide the traveler along a path to the destination.
The 3-D cues sound like they are coming from about 1 meter away from the user’s body, in whichever direction the user needs to travel. The 3-D audio, a well-established sound effect, is created by taking advantage of humans’ natural ability to detect inter-aural time differences. The 3-D sound application schedules sounds to reach one ear slightly faster than the other, and the human brain uses that timing difference to figure out where the sound originated.
The 3-D audio beacons for navigation are unique to SWAN. Other navigation systems use speech cues such as “walk 100 yards and turn left,” which Walker feels is not user friendly.
“SWAN consists of two types of auditory displays – navigational beacons where the SWAN user walks directly toward the sound, and secondary sounds indicating nearby items of possible interests such as doors, benches and so forth,” says Walker. “We have learned that sound design matters. We have spent a lot of time researching which sounds are more effective, such as a beep or a sound burst, and which sounds provide information but do not interrupt users when they talk on their cell phone or listen to music.”
The researchers have also learned that SWAN would supplement other techniques that a blind person might already use for getting around such as using a cane to identify obstructions in the path or a guide dog.
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