Label watching

Even pharmaceuticals are expected to attract attention with alluring wrappings. Most packaged products additionally carry both consumer and supplier information.

These colourful boxes are increasingly being printed during the packaging process to save time and money.

The problem: the process is too fast for human inspectors to read the printed information, risking rejects.

Is the serial number or use-by date correct? Is it legible? Is the print quality OK? Are there spots on the packaging? Researchers at the Fraunhofer Institute for Information and Data Processing IITB, in close co-operation with industrial partners, have developed an automated image analysis system to find the answers.

The PrintInspector monitors print quality not just by random checks, but continuously and in synchronisation with the production steps. Three tasks are accomplished simultaneously.

Small, locally isolated irregularities are detected during the print quality test. The system recognises poor contrast and bleeding colours as well as smudged letters or numbers.

The first test looks at fixed elements such as company logo and the names of the manufacturer and products. Variable data such as serial or batch numbers or use-by dates are verified in the second step. These values are also read by a high-resolution line scan camera with 4096 pixels at a rate of over 80 million pixels per second.

A third inspection checks not only printed areas, but the entire package for soiling, ink splashes and other imperfections.

The system inspects printed matter on all kinds of materials, such as aluminium, paper, cardboard, plastics and wood. It functions with transmitted as well as incidental light and with flat or curved surfaces.