The Shanghai Metro will soon be using a cutting-edge imaging device for passenger security checks.
The device, based on passive terahertz (THz) imaging technology, can efficiently detect dangerous materials hidden under people’s clothes.
Passengers only need to walk through a curved walkway to be checked, and if suspicious objects are detected, the device will automatically inform security staff.
However, bags will still be checked in a separate machine because the device is not able to check them at the same time.
The first batch is now being installed at Huaihai Road M. and Natural History Museum stations on Line 13.
Bowei Thaherz Information Technology Co, the company based in Anhui Province that developed and provides the devices, said they send no radiation at all into the human body.
The device absorbs terahertz waves, whose radiation is in between microwaves and infrared light waves, from the human body, as the waves can penetrate fabrics and plastics. When objects block the waves, their shapes and positions will be indicated with their materials analyzed.
While most human body check devices react to only metal objects, this device can also analyze liquids, gels, porcelain and powders, and it takes only two to three seconds to check each person, the company said.
The device is already being used at some Metro stations in Beijing, and was used at large international events such as the first China International Import Expo, which was held in Shanghai last month, and Airshow China in Zhuhai city, Guangdong Province, according to the company.
Shanghai Metro police declined to reveal exactly when and how many of the devices will be put into use, or where they’ll be located.