Researchers have developed a ‘suspicious object detection system’ that is easy to set up, reduces security screening costs and avoids invading privacy such as when screeners open and inspect bags, backpacks and luggage. Traditional screening typically requires high staffing levels and uses costly specialised equipment.
According to Jennifer Chen, study co-author and a professor in the Department of Electrical and Computer Engineering in Rutgers-New Brunswick's School of Engineering. ""This could have a great impact in protecting the public from dangerous objects."
Wi-Fi signals in most public places can penetrate bags to get the dimensions of dangerous metal objects and identify them, including weapons, aluminium cans, laptops and batteries for bombs. Wi-Fi can also be used to estimate the volume of liquids such as water, acid, alcohol and other chemicals for explosives, according to the researchers.
This low-cost system requires a Wi-Fi device with two to three antennas and can be integrated into existing networks. The system analyses what happens when wireless signals penetrate and bounce off objects and materials.
The researchers carried out experiments with 15 types of objects and six types of bags and were able to demonstrate detection accuracy rates of 99 percent for dangerous objects, 98 percent for metal and 95 percent for liquid. For typical backpacks, the accuracy rate exceeds 95 percent and drops to about 90 percent when objects inside bags are wrapped, according to Chen.
"In large public areas, it's hard to set up expensive screening infrastructure like what's in airports," Chen said. "Manpower is always needed to check bags and we wanted to develop a complementary method to try to reduce manpower."
Next steps include trying to boost accuracy in identifying objects by imaging their shapes and estimating liquid volumes, she said.
