THE VIRGINIAN-PILOT
Copyright (c) 1994, Landmark Communications, Inc.
DATE: Thursday, September 8, 1994 TAG: 9409080456
SECTION: FRONT PAGE: A6 EDITION: FINAL
SOURCE: BY DANIEL GOLEMAN, THE NEW YORK TIMES
LENGTH: Medium: 99 lines
The other day Dr. Reginald Golledge, who is blind, took a remarkable stroll through the campus of the University of California at Santa Barbara. As Golledge walked along, places and impediments in his path seemed to call out their names to him - ``library here, library here,'' ``bench here, bench here'' - guiding him through a Disney-esque landscape of talking objects.
Golledge, a geographer at the university, was testing a prototype navigation system for the blind that announced the whereabouts of objects ahead through stereo headphones mounted to a computer in his backpack, creating a virtual reality landscape.
The information came from the signals broadcast by the military's network of global positioning satellites. One day, its developers hope, miniaturized versions of this navigation device, which now weighs 28 pounds, will help blind people navigate unfamiliar neighborhoods.
``With this system you don't need to know a thing in advance about where you're going,'' said Dr. Roberta Klatzky, a psychologist at Carnegie-Mellon University who is working with Golledge to develop the navigating device, which is used in conjunction with either a cane or a guide dog.
``Blind people can find their way through totally unfamiliar terrain.''
The ``personal navigation system,'' as it is being called, promises to expand blind people's horizons to unfamiliar streets and neighborhoods. Seeing Eye dogs, by contrast, rely on their owners for cues to tell them where to go.
``This system will potentially improve tremendously the freedom of movement blind people have,'' said Dr. Michael Oberdorfer, branch chief of the Visual Processing Program at the National Eye Institute in Bethesda, Md., which is financing the research.
``A blind person could walk down the street and know not just that he was at 80th and Broadway, but what stores are around, and that Zabar's delicatessen was up ahead.''
The developers estimate that everyday use of such devices is at least a decade away, but as other technologies have shown advances can come much more quickly. Simpler devices, like eyeglasses using sonar signals to warn of looming obstacles, are much closer to market.
``But this navigation system tells you not just where there are obstacles, but your overall location geographically,'' said Oberdorfer, because it lets blind users construct a mental map of new surroundings and learn their way around.
The navigation system uses signals from a satellite-linked positioning device and a computerized map to create a ``virtual acoustic display,'' a talking map in which large objects seem to announce themselves in the headphones with the precise timing and loudness that would be the case if the objects were actually making a sound.
This allows the blind person to sense immediately their distance and direction, and use that information for guidance. While no one knows whether it is because blind people tend to develop a sharper sense of hearing, those who have tried the system say they quickly adapt to locating an object through the sounds.
``One of the crucial features of this system is that it takes advantage of sensory psychophysics - how the brain interprets signals from outside to make a map of your surroundings so you can navigate,'' Oberdorfer said.
The device relies on a triangulation of signals from four to eight global positioning satellites to find the person's precise location.
That information is transmitted to the computer, which contains the map. An electronic compass on the person's head tells the computer the exact position of the ears, so that it can then send messages calibrated to mimic a voice from the location of the object.
One advantage of the computerized system is that a blind person can preview a walk to be taken. ``You can sit in a chair at home and play the auditory beacons you'll be using so you can rehearse the walk,'' Klatzky said. MEMO: Beacons point the way
On a walk through the campus at the University of California at Santa
Barbara, a simple version of the system might simulate a steady sound
that would get louder as the user approached. As he reached the beacon
at a turn in a path, the sound would stop and a fresh sound from the new
direction would guide him in that way.
The developers are testing different messages, like ``library is 30
feet ahead, 20 feet ahead, 10 feet ahead,'' or compass readings, like
``library is at 30 degrees,'' to see which work best.
A more sophisticated version narrates a journey down the street in
terms of the main landmarks being passed.
``You'd hear `I'm the library, I'm the library,' coming from the
direction of the library, and it would alternate with other landmarks
calling their name, like `art museum here, art museum here,' to orient
you,'' said Dr. Roberta Klatzky, a psychologist at Carnegie-Mellon
University.
``Then as you reached the building you're going to, it would tell
you, `entrance here, entrance here,' coming from the right direction,''
Klatzky said.
ILLUSTRATION: Graphic
Talking maps
by CNB