A 3-D System That Works--Without the Goofy Glasses
A Stanford University researcher has developed the first system to project true three-dimensional color images, allowing people to view the same full-color animated moving picture from any angle, according to research made public Thursday.
For decades researchers have strained their ingenuity to create the illusion of a three-dimensional picture by fooling the human eye into perceiving a two-dimensional scene in high relief. Their efforts have ranged from old-fashioned stereopticons and throw-away glasses for 3-D movies to computerized virtual reality goggles and stereo liquid crystal displays.
The new system, however, is the first to project an actual three-dimensional image, experts said.
Although still rudimentary, the invention demonstrates a new technique that has potential applications ranging from medical diagnostic viewers for surgeons, air traffic control displays and battlefield management monitors to three-dimensional arcade games, cartoons and other entertainment devices.
“We believe that this technique offers a viable approach for presenting real-time, multidimensional information to a multitude of viewers . . . with no obstructed viewing regions and no special viewing eye wear,†the scientists said in a research paper published in today’s issue of Science.
An Air Force avionics expert familiar with the system was impressed by the military possibilities for cockpit displays and tracking systems. “I can see where a commander could look over an entire battlefield in three dimensions,†said Edgar J. Dulin, who has monitored the technology development for the Ballistic Missile Defense Organization.
Guy Marlor, a physicist who has seen a prototype of the innovative display system, called it “the stuff of ‘Star Wars.’ †Marlor, chief scientist at West End Partners Imaging in Fremont, Calif., said, “It is obviously in its early stages. The attractive feature is that it is a genuine 3-D article. You can walk around the darn thing and see a true 3-D image.
“That is unique in the world,†he said.
Stanford mechanical engineer Elizabeth Downing, a graduate student who spent eight years developing the system with borrowed lab space, donated lasers and after-hours help from engineering colleagues, called it “a crazy idea that [I thought] probably wouldn’t work.â€
Downing built the device with Lambertus Hesselink of Stanford, Roger Macfarlane of the IBM Almaden Research Center, and John Ralston of SDL Corp., a laser developer in San Jose that provided the system’s high-powered micro-lasers.
The system uses two computer-controlled infrared lasers to paint its 3-D pictures within a cube of special laminated glass, in much the same way that the electron beam from a cathode ray tube traces a two-dimensional image on a conventional video screen.
The energy generated at the point where the invisible laser beams intersect makes a single point of the glass glow with visible light--a precise dot like a video screen pixel seemingly suspended in space--the researchers said.
“This allows you to address a pixel anywhere inside a three-dimensional volume and then by scanning rapidly, you can draw three-dimensional images,†Downing said.
The fluorescent glass display uses several rare earth compounds that emit different colors of visible light when struck by the laser beam. By varying the chemistry of the glass, the designers are able to generate red, blue and green light in the display, mixing them to create a broader palette of hues.
In the prototype, the cube that holds the images is about the size of a sugar cube and the pictures it contains are simple three-color line drawings, which serve as test patterns. But its developers said they are confident that they can quickly make the viewing system larger while making its supporting electronics smaller.
“Currently the image is a pattern of multicolored squiggles. I can actually draw little solid volumes inside my little cubes. They can be stationary or dynamic.
“It makes me think of something out of ‘The Jetsons,’ †Downing said.
The imaging system can run on standard household current, operates at room temperature and can be viewed under normal lighting conditions.
Downing has formed a company called 3D Technology Laboratories in Mountain View, Calif., to develop commercial applications. Initial funding came from the National Science Foundation, the Navy and the Ballistic Missile Defense Organization.
Standing between the developers and any commercial application are several technical obstacles--ranging from the difficulty in manufacturing the special rare-earth glass used in the display cube to the information processing demands imposed by the enormous amounts of data needed to create each high-resolution image.
“First and foremost it is small. It has to be scaled up,†said Ralston of SDL Corp. The images are also transparent. They can be made into opaque solids, like most common objects, but special computer image processing would be necessary, he said.
“It can probably be done with commercially available technology,†he said.
Nonetheless, the challenges are daunting.
Indeed, researchers at Battelle Laboratories in the 1970s tried and failed to develop a 3-D system based on the same theory because the proper fluorescent glass materials had not yet been developed and the right solid-state lasers did not yet exist.
Still, developing a system that can project three-dimensional images is much easier than developing the technology that would allow people to create three-dimensional photographs or movies of actual scenes. The 3-D viewer’s designers expect their system to be used to visualize complex data sets--like multiple medical scans of body organs--or for animating complex engineering designs. The idea of 3-D feature-length films shot on real locations still belongs to the future.
Stephen Hart, research director of Voxel, a company in Laguna Hills that specializes in holographic displays, said the most serious problem with developing larger displays would be feeding digital data into the device fast enough to maintain the three-dimensional images. It takes 500 times as much data to render an object in three dimensions as it does in two dimensions.
To keep the moving images from flickering, they have to be renewed at a rate of 30 to 60 times a second. That would require a data flow on the order of several hundred megabytes per second, Downing estimated.
“The biggest scale-up issue is getting data into it,†Hart said. “It is doable, but you start getting into some very expensive electronics and computers to feed it.â€
Despite his reservations, Hart, who has studied the experimental system, said he was “overjoyed†when he first saw the images it produced.
“People have been throwing out ideas for 3-D displays for hundreds of years,†he said. “What she has works. The reason it looks three-dimensional is because it truly is three-dimensional.â€
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How True 3-D Works
Scientists at Stanford University have created a display device that projects a true three-dimensional color image. It requires no special viewing equipment and can be used anywhere on ordinary electric current.
The viewing cube is composed of multiple layers of glass coated with special rare-earth compounds.
Computer-controlled lasers project invisible beams of infrared light.
Actual size
So far, the viewer is the size of a sugar cube, but its designers are confident they can make viewers the size of a typical computer monitor within several years.
Red, green and blue coatings on each layer allow for color images, mixing them to produce a rainbow of hues in the same way color TV screens and computer monitors create color.
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POTENTIAL USES
Medical imaging
Current technologies like CAT-scans and MRIs already produce huge volumes of data but viewing is limited to simulated 3-D or two-dimensional “slices.†New device would permit actual 3-D viewing or body parts.
Military
True 3-D would permit battlefield and cockpit strategists to view real-time military action in three dimensions.
Games
Theme parks and video arcades are natural markets, once computers can handle the monster streams of data required by true 3-D.
