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1993-05-03
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PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA 91109. TELEPHONE (818) 354-5011
FOR IMMEDIATE RELEASE
A new digital visual filtering technology developed by a
researcher at NASA's Jet Propulsion Laboratory will offer new hope
to sufferers from maculopathy or central spot blindness. Such
people, mostly elderly, can no longer see fine detail or read,
because of degeneration of key retinal cells in the eye.
The technology is based on digital image processing
techniques first developed at JPL to enhance the first pictures of
Mars obtained by Mariner 4 in 1965. This technology is widely used
today to enhance satellite data, photographs and other images, in
applications from space to medicine. It was adapted as a
non-invasive method of relieving vision problems by Dr. Teri B.
Lawton, a psychologist and mathematician researching fundamental
visual functions in JPL's Robotics, Teleoperators, and Human
Factors Research Group.
She uses a small computer interactively to test an
individual's vision loss and then, with customized image-processing
software, to alter the spatial contrast and other properties of
printed material so that the tested observer can read it more
easily.
The optic nerve carries information from the retina, the
sensitive screen in the back of the eye, to the brain. The
connection of the optic nerve to the eyeball, slightly offset from
the center of the retina, is a small natural blind spot foreveryone. Maculopathy, however, is a loss of response in or around
the central part of the retina, in the fovea or macula, where
retinal cone cells are clustered most thickly and where visual
acuity is greatest. In this central region, we perceive fine
details and sharp edges -- for example, those defining letters on
a page.
This disability affects a small fraction of one percent
of young people, rising with age to afflict some 20 percent of
those over 75. It is regarded as a leading cause or form of
blindness in the United States and Europe, though it does not
constitute total blindness.
Being essentially a degeneration of nerve cells rather
than a problem of the lens or other parts of the eye, maculopathy
does not respond to conventional treatment or corrective lenses.
Powerful magnifiers, which may spread a few fuzzy letters over the
whole field of vision, have given some relief.
The image-processing approach, now in early stages of
development, uses closed-circuit TV equipment linked to a computer
to present enhanced and moderately enlarged words and sentences on-
screen to the reader. The computer-modified images appear blurred
to an ordinary observer, but are more easily readable by the person
for whom the enhancement formula was made.
Reading performance improvements resulting from this
computer-enhancement method are shown in increased reading speed
and reduced magnification required to see the words. In recent
experiments, Dr. Lawton found that reading rates were improved two
to three times, with 32 to 70 percent less magnification required
for reading, compared to reading unenhanced words.
A long development lies between the minicomputer-based
prototype and a practical, portable reading machine, according to
Lawton.
"The next step is a desk-top system, something like a
microfilm or microfiche reader," she says. "I would like to get
some of these out to low-vision clinics for wider use and clinical
evaluation." Books and magazines would be inserted and moved past
the TV camera's lens for reading.
To carry out this next step, JPL has formed a
collaboration with Visualtek Inc. (VTEK), of Santa Monica,
California. VTEK, formed in 1971 to provide electronic vision aids
to low-vision observers, is a producer of reading aids based on
closed-circuit TV and computer technology. VTEK will help in
optimizing the JPL technology for an effective, inexpensive
commercial product, planned to enter the market by the end of 1991.
This application draws on the same developing body of
knowledge that supports JPL's efforts to equip planetary roving
vehicles with the ability to observe and identify obstacles, or
orbital maintenance and repair systems to observe and manipulate
hardware. The effort is sponsored by NASA's Office of Technology
Utilization; program manager at NASA Headquarters is Ray L.
Gilbert.
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#1223
1/18/89 JHW note: Teri now in Seattle, at (206) 384-2767. 2/20/91.