​Senator Rand Paul (R-KY) had had enough. Walking through the L-3 ProVision active millimeter wave machine at Nashville International Airport on January 23, Paul set off a phantom alarm. When the Transportation Security Administration (TSA) screener approached Paul to pat him down, the senator insisted he be screened again rather than submit to a pat-down. TSA screeners denied that request and detained the libertarian-minded senator after he continued to refuse the pat-down. The TSA eventually allowed Paul to walk again through the scanner, which did not register an alarm that time. By then, however, he had missed his flight. He caught another flight to Washington, D.C., but the incident didn’t end there. The next day, Paul rebuked the TSA in an op-ed: “Every time we travel, we are expected to surrender our Fourth Amendment rights, yet willingly giving up our rights does not make us any safer. It is infuriating that this agency feels entitled to revoke our civil liberties while doing little to keep us safe.”

This wasn’t the only recent bad press for the advanced imaging technology (AIT) industry, and privacy isn’t the only concern. While Paul’s encounter was with an active millimeter wave machine, the other technology—backscatter—has sparked health concerns. Backscatter uses x-rays and has provoked fears of cancer, despite assurances from the U.S. Department of Homeland Security (DHS) and its Inspector General that the scanners are safe. In December, a Harris Interactive poll conducted for ProPublica found that 46 percent of respondents were against backscatter machines. While the U.S. Congress has not limited the use of this technology, the European Union banned it in November 2011.

The industry is striving to address these concerns without compromising security in the face of clear threats like the May plot by an al Qaeda affiliate in Yemen to use a bomb to bring down a U.S. bound plane. Here’s a look at where things stand, what is achievable in the near term, and the challenges that remain.

Current Technology
To date, the TSA has only approved two types of full-body scanners for checkpoint screening. As already mentioned, one is backscatter technology, which uses x-rays; the other employs active millimeter wave technology, which uses radio frequencies. The former is made by Rapiscan, the latter by L-3 Communications.

As of March, there were 379 active millimeter wave units and 247 backscatter units—or nearly 630 imaging technology units total—deployed at more than 150 U.S. airports nationwide, according to TSA spokesperson Kawika Riley. That number is set to double in the next few years.

In the past, both machines generated a naked image of the passenger; a remote screener examined the image for threats before signaling to the checkpoint screener that the passenger was clean. Even though the person seeing the image was removed from the actual person being screened, people objected to having a naked image captured.

To address that privacy concern, L-3 added a feature known as automated target recognition (ATR), which eliminates the naked body image. Instead, it uses advanced algorithms to analyze the scan, detect any potential threat, and display it on a gingerbread-man-like avatar on a screen attached to the machine. Because a naked image is never created, there is no need for persons to be remotely stationed to view them. It also eliminates concerns about whether images are being stored. Essentially, the privacy issue is removed from the equation. For that reason, for now, TSA is only buying the L-3 machines.

Currently, Rapiscan is playing catch up, but the company is expected to release its own ATR software soon. “When privacy enhancing software being developed for backscatter units meets TSA’s detection standards, TSA will test it in the airport environment,” says Riley. “TSA anticipates testing this software for backscatter units at airports this fall.”

The choice of technology is also affected by the x-ray health concerns, especially after the EU backscatter ban. L-3’s active millimeter wave scanners have also been approved for use in other countries’ airports, including Australia, Canada, Italy, the Netherlands, and Russia, giving it an advantage over its main competitor.

But L-3’s millimeter wave machines have been plagued by problems too. During recent tests of the machines, France and Germany decided against using them because of an unacceptable level of false alarms, ranging from 23 to 54 percent, according to an investigation by ProPublica. Tests of ATR-enhanced machines have found that pockets, zippers, and buttons on clothing; layered clothing or folds in clothing; and even sweat patterns trigger false alarms.

William Frain, a senior vice president at L-3, says the problems probably occurred due to outdated software. Once the machines receive the necessary software upgrades and are retested by those governments, Frain believes that France and Germany will approve the machines. (Rapiscan’s system only registers a false alarm rate of 5 percent, but the absence of ATR and the presence of ionizing radiation have made it a less attractive technology for passenger screening.)

Skeptics also argue that terrorists can beat the machines. In March 2010, Steve Lord, the Government Accountability Office’s director of homeland security and justice issues, told Congress that he was unsure whether an active millimeter wave machine would have detected Umar Farouk Abdulmutallab’s underwear bomb on Christmas Day 2009.

Then in the March 2011 issue of the Journal of Transportation Security, researchers demonstrated that terrorists had a good chance of getting the explosive PETN, the same kind used by Abdulmutallab, past backscatter machines without detection. “It is very likely that a large (15–20 cm in diameter), irregularly shaped, cm-thick pancake with beveled edges, taped to the abdomen, would be invisible to this technology, ironically, because of its large volume, since it is easily confused with normal anatomy,” researchers Leon Kaufman and Joseph W. Carlson wrote. “Thus, a third of a kilo of PETN, easily picked up in a competent pat down, would be missed by backscatter ‘high technology.’”

Throughput. Another issue is throughput, which refers to how many passengers can file through the checkpoint per hour.

Currently, airport security checkpoints can process on average 149 passengers per hour. Before 9-11, it was 350 people per hour because the screening was less rigorous. The current processing rates, according to the International Air Transport Association (IATA), are unsustainable, and simple math shows why. Between now and 2015, the IATA estimates that 700 million new passengers will take their first flight. By mid-century, IATA believes 16 billion people will fly annually. That means throughput needs to accelerate.

Some critics, like Ken Dunlap, the IATA’s global director of security and travel facilitation, say that AITs remain one barrier to making screening faster, but others, like L-3’s Frain, blame the carry-on baggage screening process for the slow throughput. Frain notes that the AIT scans take a few seconds, while carry-on baggage screening is on the rise as checked-bag fees push more and more people to bring more bags to the checkpoint.

Recent stress tests of ProVision machines conducted by TSA achieved throughputs as high as 300 passengers per hour, disclosed Frain. The only difference between the stress test and the actual security checkpoint was TSA relied solely on the ProVision machine and did not use a metal detector as backup. Test passengers still followed TSA protocols in use at U.S. airports every day.

Dunlap notes that while the time in the AIT machine may be short, the front-end and back-end of the process are not, especially when passengers aren’t used to the security protocols, according to IATA studies. “This new technology requires a different type of education for the passengers, it requires a different education for the screeners, and then it requires a resolution process,” he says, adding that some airports averaged one passenger every 75 seconds. This doesn’t mean that AITs have no role at the checkpoint, says Dunlap. They do, he notes, but primarily as a secondary screening method.

Standards
L-3’s problems in France and Germany and the EU’s ban of Rapiscan’s backscatter machine highlight a complaint all AIT manufacturers share: each country has different regulatory requirements that a machine must meet before it can be purchased and deployed at a checkpoint. The industry has formed the Security Manufacturers Coalition (SMC) to try to address the problem.

Despite being “fierce competitors,” says the coalition’s director, T.J. Schulz, the group’s member companies have joined forces to lobby the U.S. Department of Homeland Security (DHS) on issues of common concern. Coalition partners—including L-3, Safran Morpho, and Rapiscan—want DHS to provide multiyear budget plans, discuss potential threat vectors, and improve its acquisition process so that manufacturers will know what technologies the department is interested in for future deployment and what requirements they will need to meet to gain approval. With that knowledge, says Schulz, coalition partners can make intelligent decisions about what contracts to compete on and where to invest scarce research and development dollars.

The SMC would also like to see U.S. leadership on the harmonization of international technical standards and regulations. The recent EU decision to ban backscatter technology underscores this need. “Opening up formal communication and exchange of information among the key international regulators will help reduce differences and lead to an integrated approach for screening,” an SMC policy paper notes.

Dunlap agrees that a lack of shared standards across countries makes it incredibly burdensome on AIT manufacturers. “It makes the process of figuring out what the next generation of equipment is even more difficult because you have to create a machine and then you have to certify it across varying regulatory regimes,” he says.

Though EU countries have been known to fiercely guard their independence and to set their own policies—as they have on data privacy—Frain is optimistic that regulatory harmonization could occur with checkpoints within five years.

Technological Progress
Despite the challenge of these ongoing uncertainties, manufacturers are moving forward with upgrades and new products to help get passengers through the checkpoint as fast as possible without sacrificing security.

For market leaders L-3 and Rapiscan, the focus is on making their machines faster, smaller, and more efficient while adapting them to detect newer threats. “We’re always looking to improve the detection, the automated target recognition, the size of the equipment, and the throughput of the system,” says Frain. Rapiscan Executive Vice President Peter Kant says that his company is developing a machine that can scan passengers while they walk through, eliminating the need for them to stop and pose. The company has also integrated metal detection into its backscatter machine, but TSA will have to test the machine to ensure that it meets its screening requirements before it can be rolled out.

For airports that cannot currently handle Rapiscan machines because they simply can’t fit them at the checkpoint, Kant says the company has already deployed a much smaller machine at remote operating bases owned by the U.S. military. “We are taking that system, which is roughly 40 percent smaller, and applying it to the airport environment,” he adds.

Two other companies have alternative technology that can fit in checkpoints as primary, secondary, or supplemental solutions that fill particular security needs.

Morpho Detection. Morpho Detection, which is part of Morpho, the security unit of the French corporation Safran, is trying to fill security needs not currently addressed at the checkpoint. In the near future, the company hopes to deploy shoe scanning equipment and tennis racket-size screening wands that can positively verify explosives material on a passenger.

These technologies use quadrupole resonance (QR), a technique that bombards the atoms in a targeted area with radio frequencies similar to AM radio. Unlike backscatter or active millimeter wave body scanners, Morpho’s QR technology doesn’t detect anomalies, it detects explosives. The small radio frequency released by the bombarded atoms acts as a signature, allowing the technology’s detectors to identify the materials.

“Not every material has a QR signature, but it happens to be that a few explosive categories have very nice QR signatures,” says Jay Hill, executive vice president of strategy and technology at Morpho. “They often tend to be the more sophisticated high-interest explosives.”

Morpho has also developed a full-body QR portal with an integrated metal-detection capability. Europe could be a big market for that technology considering the EU’s ban on backscatter machines and France’s and Germany’s decision not to deploy millimeter wave machines because of high false-alarm rates. “We’re looking very closely at what that leaves for people screening,” Hill says. “The question then [for European airports] is ‘What is their method for screening people at checkpoints?’”

In the United States, the company believes its niche is adding capabilities to the present checkpoint since TSA has already invested heavily in backscatter and millimeter wave technology. Hill says that shoe scanners, which would eliminate the need for passengers to remove their shoes, could be dropped in almost anywhere along the security line, while the scanning wands could be deployed for use in secondary screening or used in airports that don’t have enough real estate to accommodate backscatter and millimeter wave machines.

Another advantage of QR technology, and possibly its biggest selling point in the future, is its ability to detect explosives hidden within the human body. In September 2009, a suicide bomber belonging to the terrorist group al Qaeda in the Arabian Peninsula was believed to have detonated a bomb in his anal cavity during an assassination attempt on Saudi prince Mohammed bin Nayef, the kingdom’s top counterterrorism official. Later reports said the bomb was an underwear bomb, much like Abdulmutallab tried to detonate on board a Detroit-bound flight on Christmas Day 2009. Nevertheless, the threat of cavity bombs, recently in the news again, is taken seriously.

“We’ve demonstrated pretty conclusively actually that you can do internal body scans with QR,” says Hill. “Our portal did that reasonably well, and our wand actually has been calibrated for a multiple-inch deep scan, which is pretty good.”

Currently, Morpho is working closely with DHS Science & Technology Directorate as well as TSA to get its shoe scanners and wands to U.S. checkpoints in the near future.

Microsemi. Another company seeking TSA approval for its innovative technology is Microsemi, which uses passive millimeter wave technology. Unlike current checkpoint AITs, which emit radio frequencies or ionizing radiation, passive millimeter wave technology uses sensors to measure the naturally occurring energy radiating off a passenger. Anomalies, whether metal or organic, are detected by sensors that measure the differences between natural millimeter wave energy generated by people and the objects they carry on them.

Much like Morpho, Microsemi sees its technologies filling holes currently not addressed by TSA approved passenger screening technology, according to Mitchel Laskey, vice president of security solutions for Microsemi. And also like Morpho, the company sees its hand-held scanning technology, AllClear, as perfect for conducting secondary screening, for screening in areas that cannot accommodate larger AITs, and for situations where scanning needs to be mobile.

AllClear, says Laskey, would give security agencies the ability to set up ad hoc checkpoints when necessary. But its biggest selling point is that screeners would no longer have to pat down passengers during secondary screening, precisely what Sen. Paul and others have most objected to in the screening process.

The company is also actively courting the European aviation security marketplace. It already has a presence in the United Kingdom. Laskey says that the U.K. Border Agency has been a passive millimeter wave customer going on four years now. The reasons are simple. “We don’t emit radio frequency or x rays,” he says. “We’re safe, and we pose no health concerns. And because of the way our technology operates, we cannot violate privacy, so we protect civil liberties better than any of the competitive technologies.”

Laskey would not hazard a precise forecast of when fliers could see Microsemi products deployed at airports. But he expressed optimism about the timetable. “We’re feeling pretty good that it’s probably closer than further [away],” he says.

Future Checkpoint
In June 2011, the IATA presented its vision of a “Checkpoint of the Future,” which promised travelers that they would quickly get through the security checkpoint with their clothes, carry-ons, and dignity intact. The Checkpoint of the Future is IATA’s attempt to solve the conundrum of airport security by looking for “bad people and not just bad objects,” according to Dunlap. “We cannot treat our passengers like they are the terrorists we are trying to protect them from,” he says.

IATA is working with like-minded associations, manufacturers, academics, airports, and airlines to refine the concept. Through the International Civil Aviation Organization, 19 states—including the United States, Australia, China, the EU, and Russia—are working to define approaches and common standards for a Checkpoint of the Future.

The foundation of the effort is to use passenger data to determine a flier’s risk profile before he or she reaches the checkpoint. But the checkpoint itself will need to be completely overhauled. If IATA has its way, new security technology will no longer simply get dropped into the old checkpoint, which Dunlap compares to putting a new radio into a clunker and calling it a new car. Rather, airport security will receive a redesign that gives passengers an “uninterrupted journey from curb to aircraft door.”

Early IATA prototypes of the Checkpoint of the Future show passengers strolling through three futuristic walkways labeled “known,” “normal,” and “enhanced.” “Known” passengers who have voluntarily opted into a known traveler program will receive expedited screening, while those passengers on government watch lists or about whom little is known will go through the enhanced security lane. Only passengers routed to the enhanced lane receive a body scan as a primary screening method, barring technological breakthroughs. All other passengers will go through the “normal” security lane, unless randomly selected for enhanced screening. A similar approach is already being tried out in the United States with TSA’s PreCheck known-traveler program.

According to IATA analysis, adding a known-traveler lane increases efficiency by 30 percent. Adding a separate enhanced security lane pushes it up to between 34 percent and 39 percent, a significant improvement over the current checkpoint throughput.

“[IATA] won’t settle for anything less than a revolution in the way passengers are treated at the airport,” according to Dunlap.

That revolution, however, is still about seven to 10 years away because screening technology that allows passengers to walk through the security checkpoint without stopping, unpacking, and removing laptops, belts, and jackets doesn’t exist yet. And whether it will take the shape IATA envisions remains to be seen.