Researchers at the Fraunhofer Institute for High Frequency Physics and Radar Techniques FHR in Wachtberg, Germany, have developed SAMMI (Stand Alone MilliMeter wave Image), no bigger than a domestic laser printer.

"The system detects wooden splinters lurking in diapers, air pockets in plastic, breaks in bars of marzipan, and foreign bodies in foodstuffs.

"It can even detect and monitor the dehydration process in plants and how severely they have been stressed by drought," says Helmut Essen, who led the FHR project.

"This makes the scanner extremely versatile - it's just as suitable for industrial product and quality control as for analysing materials in the lab," adds Essen, according to a Fraunhofer statement.

SAMMI's most striking feature is its ability to pick out the smallest differences in materials - differences that are invisible to X-rays. It can differentiate between the different fillings of chocolates or between rubber composites that have similar or identical absorption qualities.

Another advantage is that the scanner does not employ ionising radiation, which can damage health. It is also low-maintenance, not requiring the regular checks necessary with X-ray tubes