Nice idea - headband version anyway. Just wonder if it will be limited to
picking up return signals from a specific distance/range, and how
directional it will be, or not.
See below.
Stay well
Jacob Kruger
Blind Biker
Skype: BlindZA
"Roger Wilco wants to welcome you...to the space janitor's closet..."
----- Original Message -----
Hi All,
For your information. Appended is yesterday's Popular Science article.
Best wishes,
Peter Meijer
Seeing with Sound - The vOICe
http://www.seeingwithsound.com/winvoice.htm
Ultrasonic helmet lets anyone 'see' like a bat.
Harnessing the power of aural navigation.
By Nsikan Akpan.
“He clicks with his tongue as a way of understanding where he is in space.
This
is basically what bats do.” That’s how the science podcast Invisibilia
recently
described Daniel Kish, a blind man who taught himself how to navigate by
echolocation. But their description slightly misses the mark. While both
humans
and bats can paint visual landscapes from echoes, the pointy-eared flyers
possess a stark advantage: ultrasonic sound.
Those higher frequencies, which offer a much crisper picture of the world,
underlie the Sonic Eye, a helmet that replicates bat echolocation.
“We were wondering whether humans needed special neural wiring to
echolocate, or
whether a human brain could do it with the same audio info that's
available
to a
bat with ears designed for ultrasonic sounds,” says Stanford theoretical
neuroscientist and co-creator Jascha Sohl-Dickstein.
Invented as a side project by Sohl-Dickstein and his former colleagues at
the
University of California, Berkeley, the device features a speaker at its
crown,
which emits ultrasonic chirps like a bat. When the echoes rebound off
objects,
the sound waves travel into two bat-shaped ears - called pinna - that rest
on
either side of the helmet and help gauge the direction of the echo. Molded
from
clay, each pinna has an ultrasonic microphone embedded at the center. A
computer
program records the echoes and instantly slows them by a factor of 20.
Dropping the pace and the pitch makes the imperceptible ultrasonic echoes
audible to the human ear. Sonic Eye wearers can then use the echo delay to
judge
distance or mentally track their surroundings (see video below). In a
study
published last month, the team shows that blindfolded wearers of the Sonic
Eye
can judge whether a dinner plate, was moved left/right or up/down by ~20
centimeters - just over the length of a dollar bill.
Along with possibly assisting the blind, the new device presents a good
case
that the human mind is innately capable of comprehending high-definition
soundscapes, like bats do. Other assistive devices have tried to harvest
ultrasonic echoes, but they typically reprocess the sounds, discarding
large
amounts of spatial information.
“That’s the novelty here. A person uses The Sonic Eye to make sound
judgments
about the environment, but it doesn't do anything to the [audio] signal
apart
from downsampling it,” says Lore Thaler, a psychologist at Durham
University
in
the United Kingdom, who wasn’t involved in creating the device.
Thaler specializes in human echolocation, and her research has shown that
sound
perception for expert echolocators resides mentally somewhere between
vision
and
hearing. When blind echolocators like Kish sit in an fMRI, click their
tongues
and hear echoes, their vision centers light up with brain activity, much
like
when a sighted person sees something.
But here’s a cool twist. When both the blind and sighted try echolocation,
another brain area connected with understanding visual motion switches on.
“It seems the brain processes echolocation somewhat separately from
information
for other types of sounds,” says Thaler. “Echolocation is not just hearing
like
everything else, but a special form of spatial audition that the brain
possibly
keeps set apart from other aspects of hearing.”
For now, blind echolocators are far better at the skill than sighted
individuals
trained in the art, because many, like Kish, developed the talent as a
child. It
took months or years to perfect. The question is whether the same would
apply
with the Sonic Eye.
“In theory, you could get a finer resolution with an ultrasonic signal
versus
what an echolocator would make with their tongue,” says sensory
neuroscientist
and co-developer Santani Teng who now works at MIT. An ultrasonic bat
chirp,
due
to shorter wavelength, bounces more sound waves off an object than any
echo
made
by a human voice. An ultrasonic echo has more pieces bouncing back, which
offer
more spatial information for the brain to parcel. Bats can perceive
differences
as small as 6 mm – or the thickness of three nickels stacked on top of
each
other.
A better audio-spatial picture, using ultrasound, might expedite the
echolocation learning process for humans. Plus most human echolocators
with
blindness still use a walking cane, says Thaler, because they have trouble
with
judging elevation and detecting obstacles near the floor. She says that it
would
be interesting to see if future users had an easier time of tracking
things
on
the ground.
“You don’t want to block out sensory cues that people need to navigate,”
says
Teng. For instance, bats can modify their ultrasonic pulse based on the
size
of
the prey that they’re hunting. A blind user should be able to change the
ultrasonic output as much they want, says Teng.
But before moving into studies with the blind, the team wants to
miniaturize
their current prototype into a headband, says co-developer Benjamin Gaub,
a
Berkeley PhD student in neuroscience who is developing the Sonic Eye into
a
product suitable for the visually impaired. Currently, the Sonic Eye
requires
a laptop in a backpack that holds the device’s software, but with a little
tweaking, the simple program could be run on a microchip or a smart phone.
The
team will also consult with the blind community in the Bay Area to
customize
additional features.
Source URL:
http://www.popsci.com/ultrasonic-helmet-lets-anyone-see-bat
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