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Augmented Reality Make
VR Merge on Real World

By Steve Ditlea


Walk down the street, look at the world. This is reality. Now repeat, but wearing an odd-looking, bulky pair of glasses that place into your line of vision selective, relevant bits of data about the world; the data hovers in sight like virtual Post-it Notes, annotating your view. This is augmented reality. Glasses on, you glance to the right, at a vaguely familiar restaurant, and click a small button in your hand. Up pops text reminding you that Tom's Restaurant was the model for the diner on "Seinfeld"; not only that, but -- according to the glasses, at least -- the Morningside salad is worth ordering.


When the technology for augmented reality (AR) is fully developed, the gear won't amount to much more than glasses and some sort of small unit like a PDA. Right now, though, it consists of about 26 pounds of equipment that gets strapped to the back and to the head, along with a shoulder-perching flying saucer-shaped antenna. The Mobile Augmented Reality System (MARS), developed at Columbia University (not far from Tom's Restaurant), has been assembled from off-the-shelf technology, including a 1GHz Dell laptop with a graphics accelerator chip and soap-bar-sized batteries to power the display glasses and the critical positioning and orientation technologies. Strap on this rig and you look like a robothief on the lam from CompUSA.


But if you do strap on this rig, as I have, you begin to understand the profound possibilities of an AR system, which can superimpose computer-generated text, graphics, 3-D animation, sound, or any other digitized data on the real world. Think of what digital detail can accomplish when it pops up at your beck and call, to identify faces, or buildings, or the parts of an engine being repaired, or the flight number of a plane in the air, or the schedule of a train in a station.


Already, AR is providing real-time battlefield data for soldiers and giving physicians the equivalent of X-ray vision during delicate operations. Data is power, and AR promises to be a powerful way to insert data into the seen world.


Much of this will have to wait until later in this decade: The MARS system I wore, the first to take AR outdoors, cannot be comfortably used for much more than a few minutes at a time, even if you don't mind the gawking of passersby. And the coordination between the wearer and the data-display system needs to be better synchronized. But the principles of AR are well demonstrated, and better-working technology is on the way.


To begin, an AR system needs to know two things precisely: where you are located, and where you are looking. In order to accurately superimpose data in the field of view, the MARS system relies on two separate inputs: data from the differential Global Positioning System (GPS), which helps determine within centimeters the spot where you're standing, and data from equipment that calculates the direction of vision, down to a few degrees' accuracy. For positioning, the system triangulates signals from several GPS satellites overhead -- hence the flying-saucer antenna -- and a GPS transmitter on Columbia's engineering building. For orientation, an inertial/magnetic tracker rides on a headband above the AR glasses. This device is a combination of miniature gyroscopes and accelerometers that detect head movements along with an electronic compass that establishes the direction of the viewer's gaze in relation to Earth's magnetic field.


What's the critical factor here? "Registration, registration, registration," say AR researchers, echoing the old real estate mantra. The challenge is to accurately and continuously determine the line of sight and then align the graphics to it. Getting around the registration roadblock is less of a problem indoors, where tiny video cameras in a head-worn tracker can relatively easily read orientation and positioning bar codes or flashing infrared markers placed on a ceiling. Outdoors, however, the situation gets much more dicey. Because the tracking system currently used is sensitive to sudden variations in magnetic fields, the alignment of graphics and a street scene can be easily thrown off by even a stray remnant of 19th century technology like old iron trolley car tracks beneath asphalt. Ultimately, resolving registration difficulties may require the addition of computer vision analysis systems, with sophisticated software that can recognize the video outlines of rooms or buildings and match them to stored 3-D computer models of the real world.


Still, even if this is overcome, there will have to be a leap forward in wearable computer technology as well. During the past few years, more convenient brick-size, wearable PCs have been marketed by a number of small firms. The most prominent is Xybernaut Corp., which is selling the U.S. version of Hitachi's Wearable Internet Appliance, known as the Poma -- the first wearable computer to be sold to businesses and consumers through office supply stores and electronics retailers. Essentially a Pocket PC with a color head-worn (single-eye) display, it bears the slim profile of what researchers envision will characterize an AR appliance of the future. But despite its tricked-out design, this device is only as powerful as a typical PDA and far too limited for stereoscopic 3-D position-sensitive AR. The top AR researchers -- Steven Feiner, the developer of MARS at Columbia, and his counterparts at the University of North Carolina, Georgia Tech, and the University of Washington, along with researchers at companies such as Sony and Siemens -- estimate that it will take at least two more years before an AR-capable wearable computer will be developed.


On the Battlefield


For decades the military has been providing pilots, tank operators, and other fighters with advanced vision systems that overlay real-time combat information on computer-generated analytical data. Extending these capabilities to the fighter on the ground, however, is proving to be a much harder problem for equipment designers. Since 1992, the Defense Advanced Research Projects Agency has supported research on head-mounted displays and other AR-enabling technologies. And seven years ago, the U.S. Army launched the Land Warrior Program, which hopes to develop wearable computers as standard equipment. After significant delays in the program, Land Warrior brass now expect to field-test G.I.-wearable computer systems by 2003 and to equip all soldiers by 2008.


Almost from its beginnings, Feiner's AR work at Columbia has been funded by grants from the Office of Naval Research (ONR). An outdoor position- and orientation-sensing AR system like MARS, shrunk down, could be a boon for future Marines in combat. With its own funding from ONR, a group of engineers at the Naval Research Laboratory in Washington, D.C., is leading an effort to replicate and advance Feiner's work in a program known as the Battlefield Augmented Reality System (BARS).


"The war fighter of the future will have to work in an environment where there may be no signage, and enemy forces are all around," says Lawrence Rosenblum, director of the Virtual Reality Lab at the Naval Research Laboratory (think of recent shots from bombed-out Afghan cities, and you get the picture). "Using augmented reality to empower dismounted war fighters and to coordinate information between them and their command centers could be crucial for survival."


In the AR future, a small team of soldiers airlifted into a remote combat area will encounter terrain that has been mapped in advance. Soldiers won't see just rocks, trees, and buildings, they'll see annotated warnings: "buried mines" or "enemy stores arms in this building." As surveillance reports flow into the command center, new graphics will be broadcast to the AR gear.

A maneuver sketched with a stylus 1,000 miles away on a commander's input tablet would appear in each soldier's view of the war zone, adjusted for position.


more @ Popular Science. Learn about Augmented Reality on everiday life, workplace and hospitals.

post by vasco on 6:16 PM