Test and evaluation report for X-ray detection of threats using different X-ray functions

Improvements in the technologies available to aviation security at the checkpoint are essential for efficient and effective operations. X-ray systems in airports are designed to display images of baggage and contents, including guns, knives, other weapons, and explosives. X-ray systems have various functions to enhance the image displayed to maximize the screeners´ ability to determine if carry-on bags contain potential threats. The growing sophistication of terrorists has led to the ability to conceal improvised explosive devices (IEDs) in everyday objects. The use of X-ray image enhancement aids may help screeners detect small and artfully concealed threats giving them the best image first. The purpose of this project was to determine if any of the X-ray functions (i.e., color, crystal clear, inverse, organic stripping, inorganic stripping, high density, low density, black and white) increase X-ray screeners´ threat (i.e., IEDs, guns, knives, and other prohibited items) detection performance. An investigation to determine screener maximum performance when detecting artfully concealed IEDs was also of interest. A special set of threat bag images contained artfully concealed IEDs at full and sub-certification weights. This test evaluated experienced X-ray screeners´ threat detection of threats in X-ray images. Eighty-four screeners were tested on Rapiscan Security Products X-ray emulators at three airport sites (28 screeners per site). All screeners were required to participate in the assessment of two sets of X-ray images (400 images with color only and 400 images with other X-ray functions). Each set of bag images contained 72 threat bags and 328 innocent bags. The threat images contained: guns, knives, or prohibited items, or IEDs at full and sub-certification weights (i.e., 1/4 , 1/2 and 3/4 ). The screeners were required to decide if an X-ray image was innocent or if the image contained a threat.