Public places with heavy foot traffic like stadiums, malls and airports face security threats because crowds make it easier for people to conceal weapons. To address this security concern, MIT Lincoln Laboratory (MIT LL) created real-time microwave imaging technology, which is now licensed and integrated into a security system called HEXWAVE that will soon be used for airport security in Toronto.  

A form of microwave imaging is already used in places such as airport terminals to detect concealed threats like 3D-printed ghost guns and explosives made from plastics, liquids and other materials that metal detectors miss. However, current microwave imaging technology requires people to stop and wait for the system to screen them. As frequent travelers know, in areas that see mass numbers of pedestrians, this screening is disruptive and time-consuming.  

MIT LL developed this real-time imaging technology to do the job faster. The technology sends low-energy microwaves through people’s clothing and bags as they walk past an antenna housed in a box that’s about as tall and wide as a refrigerator. The microwaves bounce off metal, liquid and plastic and return to the antenna, which generates a 3D image of the items. Using artificial intelligence (AI) techniques, the system processes the image and classifies the items. If an item appears to be a possible threat, the system alerts an operator, who can send a security official to investigate. The AI also ensures that operators do not see personally sensitive images.  

MIT LL licensed and transferred this technology to the security company Liberty Defense Technologies, which provides multi-technology security for large public places. The system construction — which includes antenna, radio frequency transceivers and real-time image processing capability — was also licensed to Liberty. The company commercialized the technology in a system called HEXWAVE. 

A number of airports, courthouses and other venues around the country are already using HEXWAVE, while others are trialing the system. Los Alamos National Laboratory, which focuses on nuclear research and innovation, is also experimenting with HEXWAVE to meet its critical security needs.