Screening people for bombs doesn’t do much good if a suicide bomber simply pulls the trigger at the checkpoint. A new technology could detect bombs by directing a low-power radar beam at people from a safe distance–as far as 100 meters away. Signal­-­processing software reveals concealed objects without producing an under-the-clothes image that could violate privacy. The technology, developed by SET of Arlington, VA, is assisted by video analysis software designed by Rama Chellappa, a professor of electrical and computer engineering at the University of Maryland. Chellappa’s software tracks the movements of the person being screened, which helps keep the radar on target. The software could one day augment the technology even further by discerning subtle differences in the way people walk when they’re concealing heavy objects. Thomas Burns, CEO of SET, says the device, dubbed ­CounterBomber, could be ready for sale by this fall.