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Passive Terahertz Scanning Technology Helping Improve Transportation Security

By Kelly Hoggan

Passive terahertz scanning utilizes thermal imaging technology to reveal hidden weapons and explosives.

The evolution of technology over the last decade is leading to more effective security sure to benefit air travelers as well as commuters using bus, rail and other mass transportation. Passive terahertz technology is but one example of the improvement evident in transportation security screening of travelers and commuters. This form of body scanning is also less invasive, as well as less controversial, than other airport and transportation-focused body scanners. Here’s why:

No Radiation

Unlike its X-ray and millimeter-wave body scanner cousins, passive terahertz scanning doesn’t rely on different forms of radiation to perform its tasks. Rather, passive terahertz technology (known as “THz”) takes a thermal mapping or imaging approach to scanning a person’s body for prohibited items such as guns or knives. THz basically senses a human body’s heat emissions and uses them to create a visual depiction revealing the presence of any hidden explosives or weapons. THz also doesn’t require artificial illumination, which eliminates the need for radiation and thus any potential for lingering residual radiative effects.

It Improves Privacy

In the past, civil liberties advocates have raised some privacy concerns about X-ray and millimeter-wave body scanning technologies, due to the revealing images they can create when scanning people. Airports and government transportation security agencies have of course taken many steps to ensure travelers’ privacy when they’re being scanned but worry on the part of privacy advocates still lingers. Passive terahertz technology, however, eliminates such concerns because the devices record temperature variations when performing thermal imaging rather than any sort of revealing body shapes.

Though the pictures THz scanners generate are less revealing than X-ray and millimeter-wave devices they’re just as precise. Due to temperature variations between a human body and any inanimate objects on it, THz is quickly able to identify weapons and explosives on people. The device’s ability to render a thermal image highlighting any prohibited items is almost uncanny, in fact.

With passive terahertz scanning, there’s no need for searches and pat downs of travelers and commuters, and most of them will proceed through security screening without having to stop for physically intrusive examinations. THz depicts the size, shape and location of any objects blocking a person’s body heat. The thermal images it renders allows security screening officers to use their experience and training to focus only on people with suspicious items on their person.

Passive Terahertz Scanning is Efficient

THz and similar technologies are “stand-off” devices, meaning they can screen people from farther away than traditional walk-through magnetometers, X-ray and millimeter-wave booths. Depending on the type of THz system security screeners use, travelers and commuters can be scanned from distances of 30 feet or more, while simply walking up to the security checkpoint. By the time a traveler reaches that checkpoint, he or she will already have been passively scanned and can then be rapidly processed, speeding them on their way to their flight or subway train with little or no pause for physical screening.

It’s Already in Use

Passive terahertz technology has already been tested and approved by the U.S.’s Transportation Security Administration. Additionally, passive screening technologies are currently operating in Los Angeles’s Metro system of light rail and subways. The British government has also announced it will be putting THz through its paces over the course of a five-day trial soon taking place in one of London’s Underground stations. The test is aimed at determining if British Transport Police will be able to identify concealed knives on commuters without interfering with or slowing down traffic flow.

Improving Passenger Screening

With global air traveler numbers set to double to 8.2 billion passengers by 2037, the need for efficient and effective airport security screening capabilities is greater than ever. So far, passive terahertz screening is proving able to increase the number of travelers processed through security screening hourly and be consistently effective in picking out weapons and explosives. If this trend continues, then airports and government transportation security agencies would be well-advised to consider full deployment of passive terahertz technology as part of their menu of traveler screening options.

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