Dr Diana Hardmeier: The change from conventional 2D line scanner systems to 3D computed tomography (CT) is quite a substantial one. Currently, screeners are selected and trained for 2D technology. In the future, they must learn a completely new way of manipulating X-ray images. They need to know how to use the mouse to rotate the image in three-dimensional space, and learn how to handle new image manipulation functions, such as image slicing (slice images are displayed as an image sequence). This needs additional time, which could affect screening efficiency. Therefore, airport operators and manufacturers are interested in screeners using 3D systems as efficiently as possible.
In addition, it is going to be interesting to see how operators cope with laptops and liquids left in the bag - something that is possible, for instance, with ECAC EDSCB C3 standards in Europe. From an operational perspective, the transition to 3D screening is one of the biggest changes in the past decade, which is why it is important to accompany this transition process very closely and on a scientific basis.
Research in the 2D area has repeatedly shown that the following image-based factors influence detection performance: the viewpoint of a prohibited item; its superposition by other items in the bag; as well as bag complexity, resulting from clutter and dense objects within the bag. 3D could be a beneficial tool for coping with these factors, and the improved automated explosive detection functionalities support the human operator when it comes to detecting explosives.
The main challenge regarding human factors upon introducing 3D CBS technology is that the 3D rotating and slicing of bags requires screeners to acquire new skills for operating the equipment, which can be a challenge for those with limited computer skills. A phased approach allowing enough time for screeners to adapt to the new technology, and to acquire the new skills effectively and efficiently is highly recommended.
Since 2015, CASRA has been systematically analysing technological developments and possible implications for human factors. We have found that several questions need to be addressed by scientific research: do screeners need different visual cognitive abilities to work with 3D in comparison to 2D? How much training is required for 2D screeners to achieve similar detection performance with 3D? How significant are the benefits of 3D when it comes to coping with image-based factors like viewpoint, superposition and bag complexity? What are best practices when introducing 3D screening? What differences need to be considered for cabin versus hold baggage screening?
To address these questions on a scientific basis, we are currently developing a manufacturer independent 3D CT simulator. This simulator will support airports, regulators and operators with the transition from 2D to 3D over the coming years.
In summary, 3D CT technology has huge potential for improving effectiveness, efficiency and passenger experience when taking into account human factors. Our research and development is in close cooperation with users' aims to ease the transition to 3D screening, and to gain knowledge on how to achieve the best results with the new technology.