2018-11-15, Sterchi, Yanik, Buser, Daniela, Schwaninger, Adrian

2018-10, Riz à Porta, Robin, Sterchi, Yanik, Schwaninger, Adrian, Pritchard, Daniel

Threat image projection (TIP) is a widely used software function of X-ray machines at airport security checkpoints. TIP projects fictional threat images (FTIs) of actual pre-recorded threat items (mainly guns, knives and improvised explosive devices) into the X-ray images of passenger baggage before they are displayed to security officers (screeners) for screening. TIP increases attention and motivation of screeners and is often used to measure their detection performance. In order to be effective, TIP has to project FTIs in a realistic way. In other words, it should not be possible to detect FTIs by simply detecting visual artifacts resulting from TIP projection. This study was conducted to evaluate TIP quality regarding potential artifacts. First, we interviewed screeners to explore which TIP artifacts they encounter in their day-to-day work. In a second step, we conducted a rating study to quantify the identified artifacts and the quality of TIP images in general. The majority of images (80%) produced by TIP were judged by screeners to appear realistic. However, in some images FTIs were positioned inadequately: the alignment (compared to the surrounding baggage items) appeared artificial (15%) or the placement appeared physically implausible (17%; e.g. an improvised explosive device going through a heel). These two issues also significantly affected the image to appear unrealistic in general. We conclude that in most cases, TIP succeeds in projecting FTIs without creating discernable artifacts. In some cases however, the FTI is positioned inadequately, which could be improved in the future.

2018-05, Hättenschwiler, Nicole, Sterchi, Yanik, Mendes, Marcia, Schwaninger, Adrian

Bomb attacks on civil aviation make detecting improvised explosive devices and explosive material in passenger baggage a major concern. In the last few years, explosive detection systems for cabin baggage screening (EDSCB) have become available. Although used by a number of airports, most countries have not yet implemented these systems on a wide scale. We investigated the benefits of EDSCB with two different levels of automation currently being discussed by regulators and airport operators: automation as a diagnostic aid with an on-screen alarm resolution by the airport security officer (screener) or EDSCB with an automated decision by the machine. The two experiments reported here tested and compared both scenarios and a condition without automation as baseline. Participants were screeners at two international airports who differed in both years of work experience and familiarity with automation aids. Results showed that experienced screeners were good at detecting improvised explosive devices even without EDSCB. EDSCB increased only their detection of bare explosives. In contrast, screeners with less experience (tenure < 1 year) benefitted substantially from EDSCB in detecting both improvised explosive devices and bare explosives. A comparison of all three conditions showed that automated decision provided better human–machine detection performance than on-screen alarm resolution and no automation. This came at the cost of slightly higher false alarm rates on the human–machine system level, which would still be acceptable from an operational point of view. Results indicate that a wide-scale implementation of EDSCB would increase the detection of explosives in passenger bags and automated decision instead of automation as diagnostic aid with on screen alarm resolution should be considered.

2017-02, Hättenschwiler, Nicole, Sterchi, Yanik, Michel, Stefan, Schwaninger, Adrian, Jäger, Matthias

2018-10-15, Schwaninger, Adrian, Hättenschwiler, Nicole, Sterchi, Yanik, Mendes, Marcia, Hügli, David, Merks, Sarah

2018-07, Schwaninger, Adrian, Merks, Sarah, Hättenschwiler, Nicole, Sterchi, Yanik, Mendes, Marcia, Hügli, David

2017-12-07, Sterchi, Yanik, Hättenschwiler, Nicole, Michel, Stefan, Schwaninger, Adrian

2018-10-04, Sterchi, Yanik, Hättenschwiler, Nicole, Mendes, Marcia, Hügli, David, Merks, Sarah, Schwaninger, Adrian

2018-06, Merks, Sarah, Schwaninger, Adrian, Hättenschwiler, Nicole, Sterchi, Yanik, Mendes, Marcia, Hügli, David

2017-09-25, Sterchi, Yanik, Hättenschwiler, Nicole, Michel, Stefan, Schwaninger, Adrian