Miami International Airport is one of a dozen airports nationwide that have begun pilot-testing whole-body imaging machines, which reveal weapons and explosives concealed under layers of clothing.
''It allows us to detect threat objects that are not metallic and that cannot be detected by metal detectors, and items that are sometimes missed even in a physical pat-down, in a nonintrusive manner,'' said Mark Hatfield, federal security director for the Transportation Security Administration at MIA.
As passengers step inside the machine, they extend their arms and legs for several seconds, as millimeter wave technology creates an image. About 25 feet away, in a covered booth, a security officer in radio contact, views the ghostly silhouette -- with the face blurred -- on a screen. The officer determines if a concealed weapon, such as a ceramic knife, or explosive detonation cord, exists, Hatfield said.
''The image projected is more humanoid than human,'' he said. ``What's important is providing a clear view of a threat object. And the person going through the machine will never see the operator.''