Lahiru Jayatilaka (above) and Krzysztof Gajos at the Harvard School of Engineering and Applied Sciences have helped develop a new and improved means of finding and removing land mines from current and former war zones. The new system uses smartphones with the conventional metal detectors to help de-miners better visualize what they are detecting. Justin Ide/Harvard Staff Photographer |
Land
mines remain among the most destructive remnants of 20th century
warfare, continuing to slow resettlement and hinder recovery in many
former war zones.
While
mine-clearing protocols have improved substantially since World War II,
the technology used to locate buried landmines has changed little:
De-miners use metal detectors to find and identify mines. On a
battlefield strewn with metal debris, differentiating lethal mines from
benign cans, wires, and casings is enormously time consuming.
Now,
computer scientists at the Harvard School of Engineering and Applied
Sciences (SEAS) have designed an elegant system that ties in smartphones
to assist humanitarian de-miners by augmenting the information supplied
by their metal detectors. Their system, known as pattern enhancement
tool for assisting land mine sensing (PETALS),
and which will be presented at this week’s Conference on Human Factors
in Computing Systems, takes de-mining advances in a new direction.
“We
want to support people in the field with minimal invasiveness. Without
changing their sweeping style, without giving them new procedures, this
technology allows them to better visualize what they are detecting,”
explained SEAS researcher Lahiru Jayatilaka, who is working with
Assistant Professor of Computer Science Krzysztof Gajos at SEAS, James
Staszewski of Carnegie Mellon University, and Luca Bertuccelli of
Massachusetts Institute of Technology.
In
the field, de-miners use a repetitive sweeping motion to systematically
cover small sections of ground looking for land mines. When the metal
detector passes over a metallic object, it beeps. Expert de-miners are
able to visualize the auditory feedback of the metal detector, creating
in their heads an image of the object’s outline underground.
Land
mines, with their circular construction and trigger pin, have an ovoid
signature. The system designed by Jayatilaka and Gajos shows one red dot
for every beep of the metal detector. With passes over a buried object,
the picture shows an increasingly complete outline of the object’s
shape, giving the de-miner an evermore detailed picture of what may be
buried there.
“Using
only audio signals is a huge source of inefficiency. The operator has
to figure out whether it is harmful or not harmful. If they are not
completely sure, they have to go down on their hands and knees and
excavate every piece of metal as if it were a land mine,” explained
Jayatilaka.
Most
humanitarian de-mining programs operate in developing countries where
resources are highly constrained. Among the challenges Jayatilaka and
Gajos faced was designing an affordable system requiring minimal field
maintenance. Their solution involved a cheap and ubiquitous platform:
the smartphone. The final version of PETALS is designed to run on a
normal mobile device such as an iPhone, which can be mounted on a metal
detector.
In
addition to increasing search efficiency, PETALS has the potential to
help train new de-miners. In initial tests, novice de-miners performed
80 percent better with visual aid. Furthermore, Jayatilaka pointed out,
training with a visual aid can help novices understand the principles of
recognizing land mine signatures more quickly, allowing them to gain
more from training.
“Improving
the de-miner rather than the equipment is a novel way to think about
land mine removal technology,” said Jayatilaka. “It is a new direction
for the field.”
