Bomb-Detector Tops X-ray's Effectiveness
Stephan Ohr
01/09/99
CMP TechWeb
Beyond crowded cabins, lost luggage and the possibility of getting bumped even with confirmed reservations, the nagging fear at the back of every air traveler's mind is sabotage. The X-ray machines at today's airports can't find everything. Plastic explosives tucked into a portable tape player are what brought down Pan Am Flight 103 over Lockerbie, Scotland, 10 years ago. "The FAA estimates that of the half-billion bags scanned each year, there might be one -- God forbid -- with a bomb in it," said data-acquisition guru Bernard M. Gordon, president of Analogic Systems, based in Peabody,Mass. The company is about to roll out a bomb-detection system that makes clever use of DSP technology to go beyond the capabilities of conventional X-rays.
The eXaminer 3DX 6000 generates three-dimensional images of the
contents of airline luggage and carry-on bags. It takes a 360 degrees X-ray, with both high- and low-energy beams, calculates the relative density of objects and materials, and then presents this information as a 3-D,color-coded picture to a security-system operator. Thus, both metallic and non-metallic bomb materials and triggers - ordinarily obscured by tape cassette recorders, radios, and other consumer gadgets - can be revealed. In addition to explosives, the system can be used to detect drugs and other illegal contraband.
Having won FAA approval for its system in November, Analogic said it is ready to begin field trials this spring with selected airlines. The 3DX 6000, put together under contract to Lockheed spinout L-3 Communications, in New York, is designed to scan 500 bags per hour. That's roughly one every 6 seconds, Gordon said; literally the equivalent of finding a needle in a haystack.
The new entry -- only the second computer-aided tomography (CT) system
to gain FAA certification for airport security -- represents some of the most sophisticated data-acquisition and DSP analysis available, according to Analogic. The other CT system to win the FAA's nod is from InVision Technologies in San Jose, Calif. It uses embedded computers from both Analogic and archrival Mercury Computer.
"Conventional X-ray machines cannot reliably detect such bombs because
explosive material can be molded into various shapes and disguised as
commonly packed travel items, which do not provoke the attention of the X-ray operator. Such explosives also do not set off metal detectors," wrote security-industry analyst Mark Hayes in a report late last year for Security 2001, an investment analysts' conference.
That's where the Analogic system steps up to bat. In operation, the scanner circles an object 360 degrees, capturing 24 helical slices, each 22 milliseconds in duration. A total of 6,048 detectors, in 24 rows of 252, pick up the energy penetrating the bag. This energy is amplified and converted to digital format with 16-bit A/D converters sampling at 2 kilosamples per second.
This generates roughly 12 million samples per second, said Gordon. At 16 bits per sample, that means the data-acquisition system is generating a 200-megabit-per-second data stream.
This stream travels to image-processing cards designed by Analogic's Sky Computers subsidiary, in Chelmsford, Mass. Each of these cards -- the Shamrock models in the system approved by the FAA, and the newer
Excaliburs in the systems that will go into production -- packs six Sharc DSPs from Analog Devices and six custom DSPs. Each card produces
roughly 15 gigaflops of DSP processing power. Two Sky pack VME-based
computers, each with four Excalibur cards, will be used in the L-3
Communications bomb-detection system.
A single bag is actually scanned about 720 times in the six seconds it's inside the 3DX 6000 examiner, according to Peter Harris, president of International Security Systems, a newly formed Analogic subsidiary. The 100-kilovolt X-ray probe rotates at 90 rpm around the bag.
The data capture must be fairly inclusive, even for the brief interval the bag is in the scanner. But repeating the scans hundreds of times yields a fairly revealing image. It would let a trained operator find, for example, 3.5 ounces of the plastic explosive Semtex hidden behind a radio.
Wake-Up call Though lengthy investigations have ruled out sabotage as the cause, it was the explosion of TWA flight 800 over Long Island, N.Y. in July 1996 that spurred demands for upgraded security, according to analyst Hayes. At the time of the Lockerbie bombing in December 1988, he said, the FAA standards were so stringent that no systems were able to meet them under realistic airport operating conditions.
But the loss of Flight 800 was a wake-up call on the need for a coherent plan for explosives detection. The White House Commission on Aviation Safety and Security, headed by Vice President Al Gore, released a report on the subject in September 1996. A month later Congress enacted legislation that resulted in $144 million allocated for explosive-detection systems and other advanced security equipment by air carriers and airport authorities.
"Security in airports has become a more serious concern over the past
several years," a Mercury spokesman said. Since 1996, "there's been a
fairly impressive increase in the number of [detection] systems," he said. With 20 InVision systems already operating, "The FAA purchased 67 explosives-detection systems from InVision last summer for installation [at U.S. airline operations] in the United States, the U.K., France, Israel, Japan, Malaysia, Saudi Arabia, Hong Kong, Taiwan, Belgium, the Netherlands, and the Philippines," he said.
And in July, the FAA contracted for eight more systems, representing close to $1 million in revenue for Mercury, in Chelmsford, Mass. "The technology is similar to the MRI technology that both we and Analogic are deeply involved in," the Mercury spokesman said.
According to Curt Disibio, chief financial officer of InVision, there was no bomb-detection technology 10 years ago at the time of the Pan Am disaster. But the shock waves from Lockerbie led "a number of companies to initiate development to solve the problem. The collective industry, that is, people trying to find bombs with technology, has gone from probably $50 million three to four years ago to $150 million to $250 million today, certified and noncertified," he said.
Market saturation is less than 5 percent, said Disibio, noting that the Gore commission recommended spending $100 million a year for five years in this area.
The size of the explosive- and substance-detection market depends on the costs of the installed systems. They can run anywhere from $50,000 for a retrofit of existing X-ray equipment to $600,000 for a high-end system, said analyst Hayes. With 3,000 bomb-scanning systems in use around the world -- 1,400 of them in the United States -- this represents a market that could be as small as $250 million or as large as $1.8 billion.
However, most of the new CT systems for bomb scanning will cost in the
neighborhood of $200,000 to $250,000. "Several hundred thousand," said Harris of International Security Systems.
Analogic is listed in Security 2001 as major supplier to the
detection-equipment manufacturers, a group that includes American
Science & Engineering, Barringer Technologies, InVision, Magal Security Systems, OSI Systems, Thermedics Detection, and Vivid Technologies.
The two "care-abouts" in this industry, said Harris, are throughput and minimization of false alarms. That forces a trade-off, he said, between examining everything exhaustively and generating false alarms because of ambiguous readings.
Analogic, along with its Sky subsidiary, manufactures CT, ultrasound and magnetic resonance imaging systems for OEM customers. The $295
million company possesses long-term expertise in data acquisition and
DSP-based imaging. |
