A new touch-activated system projects onto walls and other surfaces and can recognize hand posture and gestures to identify individual users.
Based on the Microsoft Kinect camera, it allows more than one person to use a surface at the same time and candistinguish between the right and left hand.
The designers say the system is 98 percent accurate in determining hand posture.
"Imagine having giant iPads everywhere, on any wall in your house or office, every kitchen counter, without using expensive technology," says Niklas Elmqvist, an assistant professor of electrical and computer engineering at Purdue University.
"You can use any surface, even a dumb physical surface like wood. You don't need to install expensive LED displays and touch-sensitive screens."
The Kinect camera senses depth, making it possible to see how far each 3D pixel is from the camera. The researchers married the camera with a new computer model for the hand.
"We can isolate different parts of a hand or finger to show how far they are from the surface. We can see which fingers are touching the surface," says Elmqvist.
The team's come up with several test applications, including one that allows the user to draw a sketch with a pen and then modify it with their hands.
"We can detect gestural interactions between more than one hand and more than one user," says professor Karthik Ramani.
"You could do precision things, like writing with a pen, with your dominant hand and more general things, such as selecting colors, using the non-dominant hand."