Intelligent scales

German researchers at the Fraunhofer Institute for Information and Data Processing IITB in Karlsruhe have developed scales for supermarkets that can determine what type of produce is placed on them.

Working on behalf of the industrial weighing company Mettler-Toledo, the researchers created the intelligent scales by building in a camera and an image processing system.

In use, the system first captures an image of the product placed on the scales with the camera. An image evaluation algorithm then compares the image with stored data and automatically identifies what type of fruit it is.

Sascha Voth, a scientist at Fraunhofer IITB, said: 'The scales recognise which fruit or vegetables are to be weighed and ask the customer to choose between only those icons that are relevant – such as tomatoes, vine-ripened tomatoes and beefsteak tomatoes.' Customers then confirm the correct variety on a touch screen.

Though the scales sound straightforward enough to develop, the designers were faced with ensuring that they were tolerant to fluctuations in colour and brightness.

That is because many types of fruit are a different colour depending on how ripe they are. Bananas, for instance, range from a uniform green to yellow or even spotted brown.

What is more, the scales needed to be able to classify the fruit type even if they were packaged inside cloudy plastic bags.

The developers also had to ensure that the system was extensible to allow supermarket employees to extend the selection of fruit recognised by the scales to include new varieties.

With the development now complete, the intelligent scales are being tested in about 300 supermarkets across Europe.