3-D holographic scanner for better airport security
Researchers at Pacific Northwest National Laboratory have developed a new technology that provides 3-D holographic imaging that can rapidly identify hidden weapons—even non-metallic weapons—through the clothing of airline passengers
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September 24—The September 11 terrorist attack on the World Trade Center in New York and the Pentagon in Washington, D.C., using hi-jacked commercial airliners has sparked stringent security measures at airports across the nation. Passengers and their luggage are being physically searched before boarding every flight.
The new wideband millimeter-wave holographic imaging system developed by the Pacific Northwest National Laboratory for the Federal Aviation Administration to screen airline passengers for weapons has the potential to augment security processes and also preserve efficiency as well as a measure of personal privacy.
Concealed weapons made of plastic, ceramics, and metal can be detected with the holographic imaging system called the Personal Security Scanner. The holographic imaging system offers distinct advantages over surveillance systems that rely on metal detectors or X-ray imaging. Metal detectors cannot screen for plastic or ceramic weapons. The holographic imaging system can identify metallic and nonmetallic guns concealed under clothing, and also has the potential for detecting plastic explosives.
The goal at PNNL was to develop a harmless, visual scanning device that could identify weapons within about 10 seconds. Although X-ray imaging systems could possibly do the job, airline passengers would need to be subjected over and over to potentially harmful ionizing radiation. The holographic imaging system's millimeter-wave scanning technique is harmless.
The Personal Security Scanner uses nonharmful, ultrahigh-frequency radio waves with relatively large wavelengths in the same range as radar and satellite signals—about one centimeter. These low-power waves can penetrate clothing and other nonmetallic objects.
"To put it simply, the system rapidly scans objects and sends reflected signals into a high-speed image processing computer," said Douglas McMakin, a PNNL engineer who helped develop the technology. "The computer produces a high-resolution 3-D image from the data."
With the system's success came questions about its potential to display the unclothed physical features of a person being scanned to the operator running the machine. Since 1997, PNNL scientists have been addressing this potential privacy issue by reprogramming the system to give the operator a view of only concealed items, and not the person's image. Funding for the airport security project ended this spring, but the lab has responded to a request for proposals from the FAA in hopes of receiving additional money to further develop the technology.