Airports unpack suitcases with maths

A machine that can "unpack" suitcases electronically could soon be piloted in a British airport as a result of a breakthrough in X-ray imaging at Nottingham Trent University. Bags put in X-ray machines pass through a thin curtain of rays which produce a two-dimensional picture of their contents. If a gun was tilted in a certain direction it would not show up as a gun shape.

Max Robinson, of the electrical and electronic department at Nottingham Trent University, developed a method a few years ago that produced a three-dimensional image instead. It used two X-ray detectors at a certain angle in the machine to collect two images as human eyes do. A computer amalgamated them to produce an image on the screen similar to that seen in three-dimensional cinema.

It would have been even more useful to use techniques such as CAT scans which are used in hospitals but this technology is too expensive for airport security.

Professor Robinson's breakthrough was to realise that the data that makes up the cheaper, three-dimensional image could be reprocessed mathematically to create a series of slices on screen.

Professor Robinson's work will be on display in Nottingham next week as part of the university's contribution to SET95, the national science week.