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"Virtual Vacation" -- The Discovery Files

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A new computer algorithm developed at the University of Washington uses hundreds of thousands of tourist photos to automatically reconstruct entire cities in about a day. The tool harnesses the increasingly large digital photo collections available on photo-sharing Web sites such as Flickr.

Credit: NSF/Karson Productions

Audio Transcript:

Rome in a Day -- Digitally.

I'm Bob Karson with the discovery files -- new advances in science and engineering from the National Science Foundation.

University of Washington researchers using hundreds of thousands of tourist photos were able to construct a 3-d digital model of Rome in less than a day -- 21 hours to be exact.

Photo-stitching technology isn't new, but the algorithm the team developed is, it speeds up the process about a hundred times, making it easier to take on not just a landmark, but an entire city. It took 60,000 images of Dubrovnik, 250,000 for Venice, and the Rome model, some 150,000 pics.

The researchers went to the file sharing site, flickr and looked for images tagged 'Rome' or 'Roma.'

To try to stitch 250,000 images together used to take about a year for a group of 500 computers, because every image is compared to every image. The new method saves us time by comparing likely images for placement. It also employs parallel processing techniques.

With their Rome model, a viewer can fly around Trevi Fountain, even go inside the Sistine Chapel.

Look for this new faster method to be integrated with maps or used in the virtual world to build cites for video games or digital preservation of cities like Venice before the water does any more damage.

The digital version of a 'group' picture.

"The Discovery Files" covers projects funded by the government's National Science Foundation. Federally sponsored research -- brought to you, by you! Learn more at or on our podcast.

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