An augmented reality system to create 'digital graffiti'.

• Author: Jean, Grace V.
• Position: Inside Science + Technology

One of the indelible images from the Hurricane Katrina disaster in 2005 was that of first responders in boats and helicopters plucking stranded New Orleans-area residents off roof-tops in flooded parts of the city.

In the days following the initial rescue efforts, National Guardsmen and other workers conducted door-to-door searches for other survivors. Along the way, they spray painted arrows and large X's on walls, marking them with numbers, letters and symbols to indicate who had gone through the premises, when they had conducted the search, and any resulting discoveries.

The process, though rudimentary, was necessary given the extent of the flooding and the lack of communication equipment and tools to methodically track search-and-rescue teams' progress. But over time, the hand-painted signs became illegible as subsequent search parties added their own annotations. Historical information that may have been pertinent for future relief efforts was all but erased.

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Six years later, portable electronics and computer vision technologies have advanced to the point where a person could mark up those same locations digitally. But rather than using a smartphone or an iPad to do the trick, researchers at Lockheed Martin Corp.'s Advanced Technology Laboratories have developed a backpackable augmented reality system that permits users wearing a head-mounted video display to sketch notes and drop icons virtually in the air.

"We're looking at augmented reality as a way to blend the real or natural world with the digital or virtual world," said John Sausman, program manager of the "digital graffiti" effort.

The wearable prototype comprises a commercial laptop that connects to a pair of sunglasses with a built-in video display. Users wearing the glasses will see a video representation of the real world captured by two cameras located on the frame's opposite sides.

On the video display, option menus pop up on top of the images being captured, just as they do on digital camera displays. By donning a glove that is designed for tracking hand gestures, users can make their selections.

"It's a simple flicking of the wrist that lets you navigate through the menus," said Sausman.

In a demonstration of how troops might use the system on patrol, a program engineer points his gloved hand at a vehicle. It calculates the range by detecting how his arm is tilted. A pie-shaped menu of tasks appears on screen. He rotates his hand left or right to...