Google, researchers use your photos to make time-lapse videos

Google and the University of Washington have created 11,000 time-lapse videos showing the evolution over time of some of the world's landmarks -- all with help from the photos you may have taken.

The researchers and Google, teamed up to create 10,728 time-lapse videos (PDF) showing how landmarks around the world -- including cities, renovations to prominent buildings, and even geological phenomena -- have changed over time. The geological changes, for instance, show how over a period of several years, glaciers have retreated and a hot spring in Yellowstone developed from mineral deposits.

Creating the time-lapse videos, which typically span several years, was no small feat, the researchers noted in a research paper on the topic. They started with 86 million photos, collected from services like photo-sharing service Flickr, that are publicly available. They then used an automated process to find photos that centered on the same landmark, say Butchart Gardens in Canada or renovations to the Basilica of St. Maria of Salute in Venice. Once those images were cataloged, the researchers arranged them in chronological order and got down to the difficult task of creating the same perspective to show the changes over time.

The technique is unique in the world of time-lapse videos. Historically, time-lapse videos have been relatively easy to produce: a camera is set up in the same spot for a period of time recording any changes. After the period is up, the recordings are spliced together and a change is shown over the length of time.

The researchers, however, didn't have the luxury of easily splicing together the images, since the photos they had were taken by people around the globe and collected for their individual purposes. Perspectives were off and the researchers had to use so-called "geometric stabilization" to address that issue. Part of that process is using a complex mathematical equation that measures depth, distance, and other key points, to arrive at the focal point. The images were then placed together to keep those images focused on that point.

The research paper is designed to show a proof-of-concept and give other researchers the techniques they would need to create similar time-lapses. Perhaps more importantly, the researchers' development of an automation tool that catalogs the images and puts them all together into a time-lapse means many more such videos could be created over time.

"This capability is transformative; whereas before it took months or years to create one such time-lapse, we can now almost instantly create thousands of time-lapses covering the most popular places on earth," the researchers wrote. "The challenge now is to find the interesting ones, from all of the public photos in the world. We call this problem time-lapse mining."

Looking ahead, the researchers see even more promise. They say that the nearly 11,000 time-lapses are just the beginning. More publicly available photos are coming online each day and they can be captured and used for time-lapses. Time will also help extend the scale of currently available time-lapses.

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

Here's a video showing a time-lapse video in motion: