Bringing virtual factories to the table

Munich, Germany - Researchers at the Fraunhofer Institute for Computer Graphics Research IGD in Darmstadt, Germany have developed an tabletop touchscreen to display sequences of events of many industrial processes, which are usually difficult to visualise.

The illuminated Multi-Touch Table, which is already being used by the Coperion Group, is operated using a combination of fingers and swiping movements to present a journey through pipes and machines in a factory. Individual components can be rotated and observed by swiping a finger over them, with the same method used to watch a process in slow motion.

By drawing apart their two index fingers on the table surface, users can enlarge the image and zoom in on a detail, such as a bay wheel scooping up hundreds of thousands of plastic granules. The table provides a tangible virtual replication of processes that normally take place hidden inside networks of pipes, according to the German research group.

Acccording to IGD project manager Michael Zöllner: The table "allows customers to observe the entire process chain of plastics manufacturing and processing. They can watch in real time as the granulate flows through the pipes and regulate the speed by swiping a finger over the image."

The touch screen employs infrared LEDs, which emit light into the acrylic surface of the display at a horizontal angle. This light is internally totally reflected within the acrylic sheet, which allows none of the light to escape. A finger placed on the surface changes its reflective properties, enabling light to emerge. This light is captured by an infrared camera installed beneath the table.

Although the system is based on well-known principles, various challenges still had to be overcome. For example, the acrylic surface proved too smooth to resolve finger movements and so required a special coating.

Another problem aspect was how to project the images, said Zöllner. "To obtain a large, bright, undistorted image, the optical path has to be relatively long something that is difficult to achieve within the confines of the table below the display. We had to affect the optical path itself, by using mirrors to keep it short."