Mark Henninger (imagic) recently saw a demo of a glasses-free 3D system called Ultra-D from Stream TV Networks at the company's headquarters in Philadelphia, PA, and he wrote a great article about his experience here. Last week, I saw a similar demo, and I have to say I was just as impressed as he was.
In my case, the demo was held on a green-screen sound stage at Stereoscope, a 3D production and post-production facility in Burbank, CA. On hand was a prototype 50" UHD LED-LCD panel with Ultra-D capabilities built by Stream TV in the Netherlands. Sources included a couple of 3D Blu-ray players and a Windows PC with some preprocessed content and the Ultra-D format converter. The system was optimized for a viewing distance of 9-15 feet on a 50" screen.
Before I get to the demo, let me explain how Ultra-D works (at least, as far as I've been told). It's a 3-part solution that consists of hardware, firmware, and a proprietary content format. The hardware is a multi-layered optical system bonded to a UHD panel. The firmware controls the underlying panel at the subpixel level so it can take advantage of the optical system bonded to it. Lastly, the content must be in the Ultra-D format to be displayed correctly. Since no native Ultra-D content exists yet (tools for the creative community will be released at some point in the future), Stream TV has created the SeeCube—a module that converts any 2D or standard stereoscopic signal into the Ultra-D format in real time. As I mentioned earlier, in the demo I saw, the converter was a PC, but I was told that the SeeCube bundled with the initial screens will be a much smaller box And Stream TV's R&D facility in Eindhoven, the Netherlands, is working with a major chip manufacturer to implement the conversion functionality in a chip. The 3D rendering in the demo panel was already in chip form.
The optical system consists of several refractive and diffractive layers that, combined with how the LCD subpixels are manipulated by the firmware, project the light from those subpixels out into the space in front of the panel, creating what's called a light field. This generates stereopsis, a sense of depth when viewed with two eyes.
According to Stream TV's white paper, "Virtual and partial subpixels merge in the space and form complete and separate views for each eye of the viewer. Then the viewer's brain takes over, processing them in the same natural way as it is used to in the real world, creating a natural 3D experience. It is very different from 3D display technologies with glasses, which only project two discrete views of a scene. With Ultra-D technology, the viewing areas (light fields) are repeated in a horizontal way, and the transitions between these areas are smooth. So a viewing area is not divided into discrete viewing zones (cones) as is done in most other technologies, but the optical system creates an almost continuous light field in front of the screen."
Because Ultra-D creates a light field rather than two fixed views, it can also reproduce motion parallax, which is the effect you see when objects in your field of view seem to move with respect to each other when you move around them. This does not depend on stereopsis and can be used by those with partial or complete stereo blindness to experience a sense of depth. Apparently, Ultra-D detects objects that are partially occluding (blocking the sight of) other objects and extrapolates what you can't see behind the object in front. When you move while looking at the screen, the objects seem to move relative to each other, allowing you to perceive motion parallax.
First up in the demo was some content that had been preprocessed into the Ultra-D format, including footage of an Olympic gymnast on the pommel horse and a computer-generated space station, both of which looked phenomenal. The gymnast was shot in stereo 1080p and upconverted, while the space-station footage was generated in native 2160p stereo. Unlike passive-polarized or lenticular autostereo 3D displays—in which the vertical resolution is cut in half for each eye—the Ultra-D system combines the two 2160p images into one 2160p light field. I haven't yet been able to fully visualize the physics of this, but I will continue to investigate until I can.
Next, we looked at the 3D Blu-ray of Avatar, upconverted to 2160p. Keep in mind that the display must receive a signal in the proprietary Ultra-D format, so all signals that haven't been preprocessed into that format must be converted in real time. The amount of "depth" can be adjusted by the user, and high settings can soften the image. At 100%, Avatar looked distinctly fuzzy, but at 50% or so, it was sharp and clear with excellent 3D depth.
We also looked at a bit of the 2D version of The Avengers, and the conversion was quite good, though not as good as starting with a 3D signal. With a 2D source, Ultra-D looks at various depth cues and derives its 3D image from them. At 100% depth, the image was quite soft, but at 50%, it looked nice and sharp with a somewhat less pronounced 3D effect.
As I walked around the panel, I noticed the image wavering slightly as my eyes changed position with respect to the light field, though this wavering was less than on most autostereo displays I've seen. Grazina Seskeviciute, 3D Content Specialist for Stream TV, assured me that the company is still working on reducing this effect. And it was not a problem when I sat in one location, even if I moved my head around.
I also tested the 3D effect very close to and far from the screen. Up close, the image broke up, looking disjointed and weird. At 30 feet, it looked like a 2D image with no apparent depth at all. As I mentioned earlier, the prototype was optimized for a viewing distance of 9-15 feet, which is too far from a 50" display, especially UHD, but it's probably realistic for most viewers.
One thing I definitely wanted to ask about was watching 2D content in 2D. Seskeviciute turned down the depth to 0 and said, "you tell me." At a distance of 12 feet or so, it looked fine; I saw nothing to complain about in a relatively quick look. But up close, I could see the pixels—on a UHD display—and there were diagonal lines between them. Apparently, the refractive/diffractive optical system has a magnifying effect. Back at the optimized viewing distance, I could not see the pixels or the diagonal lines separating them. Still, I'd love to look at 2D content displayed in 2D on an Ultra-D set next to a conventional UHD set of the same size to see if there are any subtle artifacts I might have missed.
As you may already know, Ultra-D has one major competitor—Dolby 3D—and both are based on technology originally developed by Philips. Stream TV and Dolby both licensed the basic tech from Philips, then developed it in two different directions. Stream TV's new advancements include the light field, the SeeCube real-time conversion capability, and new bonding methods for mass production. I've seen prototypes of Dolby 3D flat panels, and I was very impressed by them as well. It will be interesting to see which one makes it into the consumer marketplace first. Speaking of which, Stream TV has announced that Chinese maker Hisense will make an Ultra-D TV, first for the Chinese market in early 2014, then elsewhere. The company is in final stages of negotiation with a major Japanese brand as well and expects to announce additional brand partners later this year.
Ultra-D is clearly intended for watching everything in 3D, be it 2D or 3D content, so if 3D is your thing, this is big news—high-quality, full-resolution 3D images with no glasses or fixed viewing zones. On the other hand, if you prize 2D over 3D, it might not be for you, though once you see it for yourself, you might become a convert. Either way, it's a fascinating technology, and I intend to follow its development and emergence in the marketplace.