New laser technology speeds up landmine detection process
Researchers at the University of Mississippi have introduced a promising solution. Vyacheslav Aranchuk, a principal scientist at the National Center for Physical Acoustics, presented his findings on laser multibeam vibration sensor technology at the Optica Laser Congress and Exhibition in Osaka, Japan. This new laser-based system detects landmines far more efficiently than existing methods.
"There are tens of millions of landmines buried around the world, and more every day as conflicts continue," Aranchuk said. "There are military applications for this technology in ongoing conflicts and humanitarian applications after the conflicts are over."
Currently, over 110 million landmines are active worldwide, resulting in thousands of deaths or injuries each year. In 2022 alone, over 4,700 people were injured or killed by landmines, with civilians representing 85% of these casualties, half of whom were children. Active landmines are a daily threat across 70 countries, including both current and former war zones.
Landmines are inexpensive to produce - costing as little as $3 - but their removal can cost up to $1,000 per mine, relying on dangerous and slow manual detection with metal detectors. Metal detectors and ground-penetrating radar are limited, particularly when locating plastic landmines, which are increasingly common.
Aranchuk's research team first developed a laser vibration sensor in 2019 that could detect buried objects from a safe distance using a moving vehicle. The new version significantly improves this technology by utilizing a 34 x 23 matrix array of laser beams to create a vibration map of the ground in less than a second.
"Most of the modern mines are made of plastic, so they are harder targets for traditional methods of detection that look for metal," Aranchuk explained. "That's why the NCPA developed this method of detection."
The upgraded laser multi-beam differential interferometric sensor, known as LAMBDIS, allows detection from a moving vehicle, making landmine detection both faster and safer.
Boyang Zhang, a former postdoctoral researcher at the NCPA from Nantong, China, co-authored the research. He highlighted the shortcomings of traditional approaches: "Metal detectors often generate false positives by detecting any metallic object, and (ground-penetrating radar) can be hindered by certain soil conditions or materials," Zhang said.
"In contrast, laser-acoustic detection uses a combination of laser and acoustic sensing, which allows it to detect landmines from a distance with greater accuracy. It reduces false positives and enhances safety by keeping operators farther from the detection zone."
The researchers achieve detection by creating ground vibrations and projecting a two-dimensional array of laser beams onto the ground. The reflected laser light's frequency is altered by these vibrations, which generates a vibration image. Any buried landmine, which vibrates differently than surrounding soil, appears as a red blob in this vibration image.
"The working principle is based on inference of light," said Aranchuk. "We send beams to the ground and the interference of light scattered back from different points on the ground produces signals which processing reveals vibration magnitude at each point of the ground surface."
While designed for landmine detection, LAMBDIS also has potential uses in other fields. "Beyond landmine detection, LAMBDIS technology can be adapted for other purposes, such as assessment of bridges and other engineering structures, vibration testing, and non-destructive inspection of materials in automotive and aerospace industries, and in biomedical applications," said Aranchuk.
The next phase of research will focus on testing LAMBDIS in a variety of soil conditions and for identifying different types of buried objects.
This work was supported by the U.S. Department of the Navy's Office of Naval Research under award No. N00014-18-2489.
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