Ultrasound Sensor for
Remote Imaging of
Concealed Weapons

A breadboard ultrasound sensor has been developed for remotely detecting and imaging concealed weapons. The breadboard sensor can detect metallic and non-metallic weapons concealed on a human body under heavy clothing at ranges up to 8 m and can image concealed weapons at ranges up to 5 m.

This breadboard sensor has produced the only remote ultrasound images of concealed weapons ever published, including lexan (plastic) knives and a handgun concealed under a heavy sweatshirt at 15 feet. The remote imaging by ultrasound was made possible by several new technological developments. The sensor includes a novel, highly efficient source of high-power, tunable ultrasound radiation suitable for remote imaging in air. Together with millimeter-sized, highly sensitive ultrasound detectors and high-gain transceivers, these advances make possible the centimeter-resolution imaging of concealed weapons at ranges between 1 m and 5 m.

Yet to be developed is a brassboard sensor with an imaging array of ultrasound detectors, capable of real-time, video-frame-rate imaging of weapons concealed on moving humans.

The image above shows a commercially available knife made of hard lexan plastic that passes through an airport metal detector with no chance of detection. The image below the picture of the knife is a true-scale ultrasound image of this same lexan knife underneath a wool sweater worn by a man. The image was produced with the breadboard ultrasound sensor at a range of four feet from the man.

This concealed weapons sensor was developed under the Concealed Weapons Detection Technologies program sponsored by the Air Force Materiel Command and the Defense Advanced Research Projects Agency under Contract No. F30602-95-C-0274, and with support by the National Institute of Justice.