Using millions of online photos cobbled together, we can now watch history unfold

Every photo captures a moment in time. Together, they can show how the subject of a photo changes over a longer period of time.

Previously, to capture a timelapse showing this change, one would have to point a single camera in one place for ages and then speed up the results, like so:

But computer scientists have now figured out how to create timelapses by pulling data from photos that people share publicly on sites like Flickr and Picasa. They call it timelapse mining, and the video below shows it applied to glaciers, gardens, and the Goldman Sachs headquarters tower in New York:

“We see the world at a fixed temporal scale, in which life advances one second at a time,” said the researchers, affiliated with the University of Washington and Google (pdf). “Yet these ultra-slow changes are documented by the billions of photos that people take over time. Indeed, an Internet image search for any popular site yields several years worth of photos.”

Through research that began when one of the three contributors, Ricardo Martin-Brualla, was an intern at Google, the researchers have found a way to turn these reservoirs of knowledge into “high-quality, stabilized” timelapse videos.

The researchers used 86 million public photos from the websites Picasa and Panoramio to create several thousand timelapses of popular sites, such as the Briksdal glacier in Norway. They did this by sorting through popular viewpoints of the landmark and then creating a 3D reconstruction. The images are then warped on top of each other to detect change, and then stabilized.

The team said it constructed 10,728 timelapses of 2,942 landmarks. Europe contains the highest density of sites turned into timelapses for the project, and Africa and South America have the fewest sites, based on the availability of photos in the public photo repositories the researchers examined.

“The scale and ubiquity of our mined timelapses creates a new paradigm for visualizing global changes,” the researchers said. “As more photos become available online, mined timelapses will visualize even longer time periods, showing more drastic changes.”

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