G9 User: 06/10/08

3-D Viewing without Goofy Glasses

With the release of a new set of 3-D video screens next week, Philips Electronics is bringing a sci-fi cinema standby a little closer to everyday use. Philips' WOWvx displays--which allow viewers to perceive high-quality 3-D images without the need for special glasses--are now beginning to appear in shopping malls, movie-theater lobbies, and theme parks worldwide.
The technology uses image-processing software, plus display hardware that includes sheets of tiny lenses atop LCD screens. The lenses project slightly different images to viewers' left and right eyes, which the brain translates into a perception of depth. For now, the screens are expensive and not yet marketed for home use. But Philips, which first released the technology in 2006, is working on technical improvements that will make the screens better suited for the home.
"We think this is a huge leap," says Wolf-Nils Malchow, production manager for the Munich-based Kuk Filmprodukion, an early producer of content for the displays and of promotional films for clients such as Deutsche Telekom. "It is a bit like a few years ago, when [high-definition video] kicked in. Everyone is excited about it."
A planned deployment of about 50 screens in U.S. theater lobbies has begun at the Bridge Theater in Los Angeles. South African shopping malls have ordered about 350 of the screens. Other rollouts include malls and coffee shops in Russia, European casinos, and theme parks, the company says. And at next week's Infocomm trade fair in Las Vegas, new 52-inch and 22-inch options will be added to the existing 42-inch model.
This isn't the first time that 3-D has made a splash. The early 1950s and early 1980s each saw their own fads. The 3D movies from the 1950s were filmed with two cameras, with the separate images then projected simultaneously. The familiar red-and-blue-lensed glasses were used to trick the eyes into interpreting color differences as distance. Modern 3-D movies employ more-sophisticated approaches, such as projecting the separate images in polarized light and using glasses with polarized lenses that filter out one image on each side.
But a combination of advances in computer image processing and industrial optics has allowed companies like Philips to develop their glasses-free technique.
As with earlier techniques, the illusion requires specially-created content to start with. In this case, a digital movie file effectively has two frames for each ordinary movie frame. The first is an ordinary color image, identical to what would be seen on a two-dimensional screen. A second frame, rather than showing a second offset view, encodes information about how viewers should perceive depth in the first frame. It appears as a grayscale version of the first, with white indicating foreground objects, black denoting deep background, and shades of gray indicating points in between.

Then, special PC-based hardware and software--housed in the display itself--processes the pair of images as the video is played. The information in the second frame is used to transform the original color frame into nine separate images, each slightly offset from the last, as though the camera had been moved a few inches to the side each time. All nine are then sent to the screen.
To allow viewers to perceive these images, the LCD screens are overlaid with three-pixel-wide cylindrical lenses that direct the different images into side-by-side paths. A nearby viewer will see one of these images with each eye--the first and third, or third and fifth, for example--thus producing the illusion of image depth.
The multiple images allow viewers to walk around the viewing area--a cone about 20 degrees wide--without disturbing the 3-D illusion, says Philips product manager Erik van der Tol. This cone is duplicated several times on each screen, further widening the 3-D viewing area.
The number of content producers working with the format is small, but growing. Kuk creates live-action stereoscopic films, using two cameras to film. Others, such as the London-based SquareZero, work primarily with computer graphics, which requires a less specialized production process.
"You do get really good depth perception," says SquareZero head of animation Olly Tyler. "The image seems to go into the screen and come out of it."
As with any new technology, there are glitches. With the company's 42-inch screens, the 3-D effect works most effectively only up to a distance of about 12 feet, and if you view the screen at the boundary between the three "cones," you experience garbled images. In addition, the quality of ordinary two-dimensional images on the screens is diminished. Finally, a 42-inch screen will set you back $12,000 (prices on the new 52-inch and 22-inch models being released next week have not yet been specified).
Still, while today the company is focusing squarely on the advertising and display market, it does have its eye on the consumer market. Researchers are working on expanding and smoothing the viewing area and on improving the two-dimensional viewing quality in order to make the screens entirely backward-compatible with ordinary video.
"Look a couple of years ahead, and I think this will be an acceptable technology for the home," says van der Tol. "The Hollywood scene is definitely interested." Philips is not alone; Sharp Electronics, along with a handful of small companies such as Dimension Technologies and Alioscopy, offer competing products.

Containing Internet Worms

A new method could stop Internet worms from spreading.

The spread of Internet worms could be stopped early on by using a new method to watch computers for the behavior exhibited by infected hosts, according to research recently published in IEEE Transactions on Dependable and Secure Computing. Although other methods exist to protect against worms, the new strategy is designed to minimize interference with users' normal work patterns, says Ness Shroff, a professor in the electrical-engineering department at Ohio State University, who was involved in the research. The researchers envision the technique being used in corporate networks, where it could identify computers that need to be quarantined and checked for infection.
Internet worms can be enlisted to launch denial-of-service attacks, which flood a website so that legitimate users can't access it, or install back doors that can be used to create botnets. Large numbers of infected computers could significantly slow Internet traffic, even if the worms do nothing more than spread.
The Purdue University and Ohio State method of preventing worms from spreading works primarily for a class of worms that scans the Internet randomly in search of vulnerable host machines to infect. One such worm was Code Red, which infected more than 359,000 computers in less than 14 hours in 2001, and ultimately caused an estimated $2.6 billion in damages. Although this type of worm has been around for some time, Kurt Rohloff, a scientist in the distributed systems technology group at BBN Technologies, says that it is still dangerous. These "are a very simple class of worms that's very easy to develop and program, but at the same time, they're not as easy to contain," he says. "If we could understand these fairly simple but still problematic worms, we could hopefully address the more so-called devious worms."
The researchers base their strategy on a new model that they designed for how worms spread. Many existing models are based on an analogy to the spread of epidemics, Shroff says, but they are more accurate at later stages of an infection. The researchers' model was particularly designed for accuracy in the early stages of infection, and it revealed that the key to whether or not a worm can spread successfully is the total number of times that an infected host scans the Internet in attempts to find new hosts to infect.
While other methods of containing worms have focused on monitoring computers for changes in the rate at which they scan the Internet from moment to moment, Shroff says that this can interfere with users' daily activities. "Scan rates fluctuate a lot, so if you go online, you may scan a lot of times during a very short period of time, and then not scan at all," he says. "We felt that the scan rate was too restrictive and could interfere with the normal operation of the network." By monitoring the volume of scans over a longer period of time, he says, it's possible to contain worms while keeping the threshold too high for ordinary users to raise alarms. Software could monitor the number of scans each computer on a network sends and quarantine any computers that exceed that number. Shroff hopes that changing the criteria for suspecting infection in this way will reduce the likelihood that legitimate scans of the Internet would be flagged as worm activity.

"In a sense, what we're doing is taking advantage of the fact that this worm is trying a lot of things and missing many times, and each time it misses, it's giving out some information," Shroff says. Although the system is designed for dealing with scanning worms that seek vulnerable hosts at random, the researchers have also adapted it for worms that target their attacks at specific local networks.
Shroff believes that the system could best be deployed on corporate networks, particularly in situations in which extra computers are available that could cover a workload while possibly infected computers are examined. It might not work as well for small businesses or on home networks, because taking a computer offline could be too large of a disruption for users, he says.
Rohloff says that he could imagine such a system being effective, but he cautions, "The bias, of course, would be that it would protect local networks from infections that are already present in the network. It wouldn't do as much for protecting networks from infections that come from the outside." He adds that while the researchers' model and initial simulations look good, he would be curious to see a more thorough analysis of how often the system suspects a computer of being infected with a worm when no worm is actually present.
The Purdue and Ohio State researchers suggest that future work could search for ways to adapt their tools for ever more targeted worms. Shroff says that while he and his colleagues are now concentrating on stopping worms at the level of host computers, another possible direction could be to make software that would allow routers to watch for suspicious traffic patterns. While such an approach could allow a relatively large number of computers to be monitored from a single point, it would also require significant changes to how routers operate. While they currently keep track of only the destination of Internet traffic, they would have to begin keeping track of its source as well.