Touch-sensitive video-screen floor is in step with you

 
 
A prototype floor that senses your every step and displays interactive video could one day bring strange sights and new possibilities into your home

GLANCE down at the interactive floor in Patrick Baudisch's lab and you will not see your reflection in the glass. Instead, you will find your computer-generated doppelgänger, wearing a facsimile of your clothes, which walks and moves just like you do. It seems to be stuck to your feet (see picture).

This mirror world is one of the applications Baudisch and his colleagues at the Hasso Plattner Institute in Potsdam, Germany, developed after building an 8-square-metre pressure-sensing floor that can recognise people by their weight, track their movements and display video for them to interact with. The idea is that the pressure-sensing technology could lead to a raft of ways to control objects in your home, play games, or assist older or disabled people.

For instance, to play a version of indoor soccer, the floor generates a CGI football that can be kicked about by the people in the room. Or if someone sits on the floor, the system recognises who they are by their precise weight and flips a TV on to their favourite channel. Similarly, an elderly person's activity levels could be monitored.

Developed with funding from Microsoft Research in Cambridge, UK, Baudisch envisions the device as a forerunner to pressure-sensing floors in people's homes. His team will present the invention, dubbed GravitySpace, at the Conference on Human Factors in Computing Systems in Paris, France, in April.

The team's prototype consists of a slab of 6.4-centimetre-thick glass installed in a hole cut into a standard floor, and an infrared camera and high-resolution video projector in the room below that tracks footprints and beams video up onto the glass.

Infrared LEDs surround the flooring, which is also coated with a rubbery, pressure-sensitive film. A footstep on the surface makes the film interfere with the infrared light, creating an image of the footprint that is captured by the camera below. "This pressure sensor is of such high resolution that the floor can recognise anything from shoe prints to fabric textures to someone's knees," says Baudisch.

Software running on a linked computer recognises what those objects are doing and generates relevant video in response. In the football app, for example, the floor measures the rate of change of pressure on the non-kicking foot to determine when you are kicking - the floor cannot "see" the foot that is in the air - and the ball is moved in response.

"It's an extremely exciting research result," says Ken Perlin, at New York University. "The future of computer interfaces is to become more sensitive to people's needs. A floor that understands where you are and what you are doing is a logical step in that direction."