Precisely which applications is hard to predict, says Harrison. “It’s an enabling technology, just like touch screens. Touch screens themselves aren’t that exciting,” he says—it’s what you do with them. But the team has built several sample applications; one allows users to virtually annotate a physical document, and another incorporates hand gestures to allow OmniTouch to infer whether the information being displayed should be made public or kept private.
“Using surfaces like this is not novel,” says Pranav Mistry a researcher at MIT’s Media Labs. Indeed, two years ago, Mistry demonstrated a system called SixthSense, which projected displays from a pendant onto nearby surfaces. In the original version, Mistry used markers to detect the user’s fingers, but he says that since then, he has also been using a depth camera. “The novelty here [with OmniTouch] is the technology,” he says. “The new thing is the accuracy and making it more robust.”
Indeed, the OmniTouch team tested the system on 12 subjects to see how it compared with traditional touch screens. Presenting their findings this week at the ACM Symposium on User Interface Software and Technology in Santa Barbara, the team showed it was possible to display incredibly small buttons, just 16.2 millimeters in size, before users had trouble clicking on them. With a traditional touch screen, the lower limit is typically around 15 millimeters, says Harrison.