In today’s Academic Minute, Dr. Carey Rappaport of Northeastern University explains the development of a new generation of body scanners that will provide an increase in security and privacy for airline passengers.
Carey Rappaport is a professor of electrical and computer engineering at Northeastern University. His research interests include antenna design, computational modeling, biomedical microwave design, and subsurface sensing design. He has authored more than 300 articles for conference presentations and technical journals. He earned his Ph.D. at the Massachusetts Institute of Technology.
Dr. Carey Rappaport – Full-Body Scanners and Privacy
My research concentrates on electromagnetic waves, and how they can be used to sense and image. My research group uses waves to penetrate layers and create images of concealed objects; particularly threatening ones that terrorists might have bound to their bodies. We use a special type of radar that easily senses through clothing, to generate a detailed picture of anything man-made on a person’s skin.
Millimeter-wave scanners are a form of very high frequency radar, which uses the reflection of microwave energy to determine what an object is made of and how far away it is. Millimeter-waves can distinguish between metal and non-metal objects, and between objects with high water content and drier matter. Because guns, knives and other weapons are usually metallic, their shapes can be picked out from the background skin. Unlike skin, explosives have very little water, offering a clear contrast as well. Because of the short wavelengths of millimeter waves, these scanners can focus in on features as small as one-quarter inch.
As for health concerns, the only proven biological effect of micro and mm-waves is heating. Unlike x-rays, and UV, radio frequency energy is only harmful when the power is extremely high While we use microwave ovens to cook food, unless you are exposed to many watts of power there are no harmful effects of microwaves. Radar body scanners, like cell phones and police traffic radar, are completely safe.
The privacy concerns of clothing penetrating sensors are somewhat overblown. The scanner resolution is coarse enough that images look out of focus and indistinct. The skin surface is not imaged specifically, so it appears that individuals are wearing leotards or body stockings. One important aspect of our advanced imaging research is that better imaging may actually improve privacy by making it easier for computer software to determine manmade objects on the body. If a computer can make a more reliable determination, there is less need for a human to view the images.