The underwear bomber's thwarted attempt to blow up a Christmas Day flight jeopardized President Barack Obama's plans to close Guantanamo Bay prison, refueled advocacy concerns about passenger privacy and forced Yang Cai to revisit an algorithm that identifies the curvature of a female breast.
Sitting in a Carnegie Mellon University office surrounded by plaster of Paris molds of the human figure, Dr. Cai explained how his algorithm could put to rest qualms about overexposure from 3-D body scanners at security checkpoints.
His algorithms measure the human frame and identify the breast and genitalia areas. The system then automatically blurs those regions, blacks them out with a bar or replaces the features with dummy human parts.
"Every man could be Arnold Schwarzenegger, and every woman could be Marilyn Monroe," he said.
But airport security has never been a place for fantasy. The holiday scare and recent news that the Transportation Security Administration plans to deploy 450 full-body scanners nationwide have government officials planning for legislation and passengers preparing for lines.
Everyone is worried about who's looking at what. Two researchers at Carnegie Mellon's CyLab are working with security technology that assuages privacy concerns. Dr. Cai's research offers an automatic censor for certain body parts and the CyLab Biometrics Center's programs recognize faces and irises.
Despite the fact that Dr. Cai's system blocks out private parts, it will identify an object hidden around those regions.
Dr. Cai, who founded CMU's Instinctive Computing Lab, eventually envisions a system that can wipe out the body image entirely, picking up only weapons, which will appear to be floating in space.
His research, started in 2000 and published six years later, uses "intrinsic landmarks" to identify the body's regions of interest.
The unit of measure is the human head. After that size is determined, the system knows that the breast region is one-head-size down from the chin, and can map out the rest of the body from there.
"It's instinctive computing," he said. "We use one object to measure another object."
Downstairs at the CyLab is the Biometrics Center, which permits visitors in the door only after scanning their iris. (The center's director, professor Marios Savvides, also has a key.)
That same kind of iris scan technology is seen by Dr. Savvides and his 20 student assistants as a viable and eventual alternative to fallible security methods, such as body scanners and behavioral analysts.
The problem is that iris scans work now only with highly cooperative subjects who strike the right pose in the right lighting for the iris to be picked up.
A machine designed to mimic an airport metal detector sits in the back room. Dr. Savvides' students double as involuntary models.
As each walks through the machine, his or her face is illuminated in infrared and the iris is captured by the camera. The machine matches the iris with those stored in its database. The computer identifies the subject and says, "Nice to see you."
Dr. Savvides sees the eventual possibility of this technology identifying bad guys whose irises have been stored.
But these are compatible guinea pigs who also need a good grade. What about suspects actively avoiding the camera?
Those are technologies that the lab is "at the edge of," Dr. Savvides said. That includes a camera that finds a face and can follow it as it moves up to 60 feet away. He's also working on a system that identifies irises from a distance for the Department of Defense, which could take about a year to develop.
Cameras with a far-reaching radius can help to identify a potential terrorist before he reaches the scanners at a security checkpoint, which Dr. Savvides calls "the last failure point." Long-range cameras could track and identify a suspect before he or she gets close to security or soldiers.
The lab mostly works with government contracts, although it had more industry work before the recession, said Dr. Savvides.
Other software takes a 2-D image (like a regular photo) and creates a 3-D image of the head from it. That could lead to facial recognition from any angle. The faces used to demonstrate this technology in the lab are like high-tech dorm room posters: Megan Fox and Angelina Jolie are frequent screen guests.
The team is working with the FBI to map out the human face to help with image profiling. They currently have 79 facial points identified, with the hope of using them as a template for a system that can recognize a face that appears nervous or finicky.
Ironically, it's the most ostensible and human traits that still trip the technology -- things such as facial hair or eyeglasses.
Dr. Savvides wants to work toward a technology that recognizes if the image-captured person is scarred or wearing a hat.
Dr. Cai's work also is in the research phase. His projects were funded by the National Science Foundation and the Army Research Office.
Once a new technology is ready, the Transportation Security Administration review process can take several years, said TSA spokeswoman Ann Davis. Technology is tested at a facility at Reagan National Airport in Washington, D.C., and, if approved, is taken on as part of a pilot program at select airports across the country.
Whole-body imagers were first deployed in airports in Phoenix in 2007. The TSA has purchased 150 scanners and will buy another 300 to be distributed sometime this year.
By comparison, Pittsburgh's airport security looks decidedly low-tech. But Ms. Davis said the airport's arsenal of metal detectors, luggage scanners and explosive trace detection machines is comparable to those in most sites across the country. Pittsburgh also has uniformed officers trained in behavior detection.
Though the number of total-body scanners the TSA will have matches the number of commercial airports at 450, Ms. Davis said that doesn't necessarily mean every airport will have one.
Still, plans of a massive scanner deployment have some advocacy groups worried.
"Do these store and record images of American passengers stripped naked? The answer is yes," said Marc Rotenberg, executive director of the Electronic Privacy Information Center.
Mr. Rotenberg said the diversity of bomb-making materials complicates the usefulness of body scanners that can't detect liquid or powder components.
He finds sacrificing privacy misses the big-picture problems, such as an erosion of intelligence or a bureaucratic failure to communicate about a specific threat like the Christmas Day bombing suspect, Umar Farouk Abdulmutallab.
"Oftentimes we're asked what the harm is in the privacy realm. But this intrusion is the compelled disclosure of one in undress by the government," he said.
But Dr. Cai has found concerns over the systems to be unique to the United States, adding that such a system wouldn't cause much concern in parts of Asia, which have populations more obsequious to the government, or in Europe, where anyone looking for a thrill heads to the beach and not the airport.
Dr. Savvides, too, has little concern about his technology leading to a police state.
"Have you ever thought about how many cameras are in a casino?" he asked.
Erich Schwartzel can be reached at firstname.lastname@example.org or 412-263-1455. First Published January 24, 2010 5:15 AM