Sounds
attract camera
By
Chhavi Sachdev,
Technology Research News
When Steven Stills penned the lyrics, “Stop!
Hey, what's that sound? Everybody look what's going down," he was describing
a natural phenomenon that we seldom think about consciously -- sounds
make us look. When people clap, shout, or whistle to get our attention,
our heads instinctively swivel towards them. Imagine the potential of
a robot that reacts the same way.
University of Illinois researchers are taking steps towards that goal
with a self-aiming camera that, like the biological brain, fuses visual
and auditory information.
In time, machines that use vision systems like this one could be used
to tell the difference between a flock of birds and a fleet of aircraft,
or to zoom in on a student waving her arm to ask a question in a crowded
lecture hall.
The self-aiming camera consists of a video camera, two microphones, a
desktop computer that simulates a neural
network, and a second camera that records chosen information. The
microphones are mounted about a foot apart to mimic the dynamics of an
animal’s ears.
The heart of the researchers' system is a software program inspired by
the superior colliculus, a small region in vertebrates’ brains that is
key in deciding which direction to turn the head in response to visual
and auditory cues. The colliculus also controls eye saccades -- the rapid
jumps the eyes make to scan a field of vision.
In determining where to turn the camera, the system uses the same formula
that the brain of a lower level vertebrate like a barn owl uses to select
a head-turning response, said Sylvian Ray, a professor of computer science
at the University of the Illinois at Urbana-Champagne.
The computer picks out potentially interesting input and calculates the
coordinates where sound and visual motion coincide, Ray said. "The output
[is] delivered to a turntable [under] a second camera. The turntable rotates
to point the second camera at the direction calculated by the neural network."
In this way, the second, self-aiming camera captures the most interesting
moving object or source of noise on film for further analysis, saving
a human operator the chore of sifting through all the data.
The camera re-aims every second toward the location most likely to contain
whatever is making the most interesting noise. Because it always chooses
an estimate of the best location for all available input, the system works
even if several motions or noises happen at once, according to the researchers.
The self-aiming camera could be used to pare down meaningless data captured
by surveillance systems that use several cameras to take pictures of their
surroundings, according to Ray. It could be used as an intelligent surveillance
device in hostile environments, and for ordinary security, he said.
To have the system differentiate among different types of inputs, the
researchers plan to add specializations that will give certain inputs
more weight. In nature, different vertebrates respond to particular targets;
a cat likes different sounds and motions than an owl, for instance, said
Ray. "One specialization of the self-aiming camera would be to train it
to like to look for human activity," he said.
“This is a nice example of exploiting ideas from biology to better engineer
systems since this pairing of stimuli increases the reliability and robustness
of the self-aiming camera,” said John G. Harris, an associate professor
of electrical and computer engineering at the University of Florida. A
better understanding of the underlying neural mechanism is still needed,
he said.
Eventually the system will have to deal with multiple objects as well
as noise and room reflections, Harris said. “Such a system needs an attention
mechanism in order to attend to objects of interest while ignoring others.
This is a higher level behavior that requires different sets of neurons
and is beyond the scope of the current demonstrated system,” he said.
The system could be in practical use in two to three years, according
to the researchers. Ray's research colleagues were Thomas Anastasio, Paul
Patton, Samarth Swarup, and Alejandro Sarmiento at the University of Illinois.
The research was funded by the Office of Naval Research.
Timeline: 2 to 3 years
Funding: government
TRN Categories: Neural Networks; Computer Vision and Image
Processing
Story Type: News
Related Elements: Technical paper, "Using Bayes' Rule to
Model Multisensory Enhancement in the Superior Colliculus," Neural Computation
12: 1141-1164.
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July
25, 2001
Page
One
Sounds attract camera
Interface lets
you point and speak
Quantum logic counts
on geometry
T-shirt technique
turns out flat screens
Rating systems
put privacy at risk
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