Touchable Holograms Place Star Trek's Holodeck Within Our Grasp

Holograms are cool; there's no denying it. They have huge potential as immersive entertainment, but until now they've fallen short in providing true verisimilitude because they engage only the eyes and ears. But that all changed last week at Siggraph 2009 in New Orleans, where a team of researchers from the University of Tokyo demonstrated a process they've named airborne ultrasound tactile display, which enables holograms to be felt as well as seen. If Luke Skywalker had had this technology a long time ago in a galaxy far, far away, he would have been able to give Princess Leia's hologram a high five.

To give holography this added dimension, a beam of ultrasonic waves is directed towards the viewer's hand, creating the illusion that the holographic object is in contact with the skin. Completing the package, two Wiimotes -- controllers from Nintendo's Wii gaming system -- track the position of the hand and add the visual stimulus so the user can imagine the sensation of a bouncing ball, falling raindrops or a tiny animal running in a circle on the palm.

The team's abstract explains it thusly: "The display radiates airborne ultrasound, and produces high-fidelity pressure fields onto the user's hands, without the use of gloves or mechanical attachments...The airborne ultrasound can be applied directly onto the skin without the risk of penetration." Which is a relief, since there's no way yet for Captain Picard to grab a Tommy gun and blow away some Borg drones with holographic bullets, as he did in Star Trek: First Contact.

It's a long way from the old "floating quarter," and the implications are thrilling if a little unsettling. We've grown accustomed to double-checking the information our eyes and ears provide. But we haven't really learned to mistrust the signals sent by our skin. Fortunately, we have time to adjust to this new technology, since the method is still a long way from holodeck-caliber realism. (Sorry Trekkies, those Counselor Troi fantasies will just have to wait.)

Not that we should be surprised at the relative lack of advances in the field: With the exception of Star Trek, science fiction usually depicts holograms as confined to visual and auditory applications, as with Lori's see-through tennis instructor in Total Recall. The holographic screens in Minority Report merely portray images on what (now) looks like a giant iPhone -- you can move them, but they can't move you. The same goes for Tony Stark's hologram of his armored suit in Iron Man. And Logan's Run, one of the first movies to feature a holographic sequence, is content merely giving Michael York several rainbow-colored, spinning heads during the interrogation sequence. So '70s!

The take-home message? It will likely be some time before airborne ultrasonic tactile display is anything more than a curiosity -- or before holograms are convincing enough to challenge our ability to distinguish reality from fantasy. Marty McFly puts it best when confronted by a giant hologram advertising Jaws 19 in Back to the Future Part II: "The shark still looks fake."

http://blogs.amctv.com/scifi-scanner/2009/08/touchable-holograms-in-scifi-movies.php