X‐Ray Imaging of Baggage for Agricultural Contraband

Real‐time X‐ray inspection for agricultural contraband has been tested during unloading of checked airline bags on international flights. Selected flights were imaged during five weeks of peak travel at San Francisco International Airport (SFO). It was shown that separating X‐raying and search in time and space was operationally feasible. All X‐ray images were digitized and stored on disk. Bags were tagged for image recall during later search. Image enhancement outlined shapes of rounded food items, such as fruits. Dried food was detected visually, using texture. Suspected bags were marked before release to passengers. Travellers carrying marked bags were identified and directed to manual search stations. Image recall at search was shown to be helpful in selecting bags and aiding search. A total, permanent system, consisting of two X‐ray inspection stations and six recall computers with video plus all required subsystems is estimated to cost $225,000, require two to three X‐ray observers/shift (plus search staff) and exhibit a mean time between failures (MTBF) of three months. Such a system would allow X ray and selection of up to 600‐800 checked bags (400‐540 travellers) per hour on a sustained basis.