MIT Creates New Glasses-Free Stereo-3D TV Technology

Glasses-free 3D is something available on just a handful of TVs, which manage it only through complicated hardware, and at no small cost.

Still, the effect is pretty smooth and no more tiresome for the eyes than glasses-assisted technology, from what we've been able to gather.

There is one more accomplishment that tech experts are looking for: holographic television, which offers a different perspective at the action, depending on the angle from which one beholds the TV.

Researchers from the Massachusetts institute of Technology (MIT) claim to have created something of the sort.

Called Tensor Display, it uses several layers of liquid crystal displays (LCDs) with a refresh rate of 360 Hz per second.

The technique is different from the one used in Nintendo's 3DS, which has two layers of LCD screens (the bottom for light and dark bands and the top for the two slightly offset images).

The problem with this old method (a century old really) is that the only way so far known for creating multiple perspectives would rely on complicated hardware and algorithms. Hundreds of perspectives would have to be produced in order to suit a moving viewer, and that means that too much info has to be displayed at once.

Every frame of the stereo-3D video would need the screen to flicker 10 times, each with a different pattern. Thus, a convincing stereo-3D illusion would need a 1,000 Hz refresh rate.

MIT's Tensor Display lowers that requirement by using a higher number of LCDs, although it does bring another problem: the pattern calculation becomes more complex. Fortunately, the researcher had a convenient factor to exploit: not all aspects of a scene change with the viewing angle. This reduced the amount of information that needed to be sent to the LCD screens.

The end result was a panel that produces stereo-3D images based on calculations similar to those behind CT, X-ray and computed tomography, of all things (they produce 3D images of internal organs).

The Media Lab researchers will demo a Tensor Display prototype at Siggraph 2012 (5-9 August), made of three LCD panels. A second model will have two LCDs with a sheet of lenses between them (refract light left and right), primarily for wider viewing angles (50 degrees rather than 20).

Practical and commercial applications should appear soon, or at least sooner than any alternatives.

“Holography works, it’s beautiful, nothing can touch its quality. The problem, of course, is that holograms don’t move,” said Douglas Lanman, a postdoc at the Media Lab.

“To make them move, you need to create a hologram in real time, and to do that, you need little tiny pixels, smaller than anything we can build at large volume at low cost. So the question is, what do we have now? We have LCDs. They are incredibly mature, and they are cheap.”