3-D mashup of Rome from Flickr pics

UNC CHAPEL HILL (US) — Using millions of images from sites like Flickr and a single computer, researchers can create 3-D models of landmarks, like the Roman Coliseum, in less than 24 hours.

The system was devised by Jan-Michael Frahm, research assistant professor of computer science at the University of North Carolina at Chapel Hill and colleagues at the the Swiss university ETH-Zurich.

To demonstrate the technique, the researchers used the three million images of Rome available online to reconstruct all of the city’s major landmarks. They also reconstructed the landmarks of Berlin in the same manner.

The process provides a far richer experience and is an improvement of more than a factor of 1,000 over current commercial systems, Frahm says.

“Our technique would be the equivalent of processing a stack of photos as high as the 828-meter Dubai Towers, using a single PC, versus the next best technique, which is the equivalent of processing a stack of photos 42 meters tall—as high as the ceiling of Notre Dame—using 62 PCs,” he says.

“This efficiency is essential if one is to fully utilize the billions of user-provided images continuously being uploaded to the Internet.”

One advantage of the 3-D models compared to viewing a video of a landmark is that the Internet photo collections used to construct them show the scene at different times and under different lighting and weather conditions, potentially creating a richer experience for viewers.

If video is available, however, the technology can utilize it as well, and using video shortens the processing time needed for reconstruction of the models.

Eventually the models could be embedded, for example, into common consumer applications such as Google Earth or Bing Maps, allowing users to explore cities from the comfort of their homes. Other applications could prove useful to travelers.

“You might be able to take a picture with your cell phone of a monument that would not only give you information about that monument, identifying it from the image, but could also tell you your location more precisely than even GPS,” Frahm explains.

The technology could be a building block for disaster response software, Frahm says. For example, an aircraft could be sent to take video of the aftermath of a hurricane, and the resulting 3-D model could be used to assess damage from a remote location, saving time and money.

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