How Google researchers turned millions of Flickr images into time-lapse videos

Researchers at Google and the University of Washington mined 86 million publicly available images to create time-lapse videos of famous landmarks. The team's code sorts the images by date, stabilizes them, and normalizes their perspectives and aspect ratios.

You’ve probably seen time-lapse videos in which filmmakers placed a camera in a particular spot and recorded footage for hours or days before compressing the passage of time, revealing a flower blooming, a city waking up and beginning to bustle with activity, or the stars appearing to move across the night sky. Now, researchers at Google and the University of Washington are producing crowdsourced time-lapse videos, assembled from more than 86 million public pictures posted online, on sites such as Flickr and Picasa.

The researchers started by grouping more than 86 million photos by location. Some monuments and landmarks are photographed thousands of times per year by visitors, so the researchers took those locations and sorted the photos from oldest to newest. Then they used computers to slightly distort the perspective of the photos, giving them the appearance of having all been taken from the same spot. Finally, the researchers smoothed out the images so that when they were played back in order they gave the illusion of having been taken at perfectly regular intervals.

The results, some of which are available on the YouTube channel of the project’s lead researcher, Ricardo Martin-Brualla, show glaciers advancing and retreating, foliage blooming and dying with the seasons, and waterfall streams emerging and drying up. They also show new construction projects, such as the Goldman Sachs Tower in Manhattan, being built; and other buildings, such as the Basilica of St. Maria of Salute in Venice, being renovated. One time lapse even shows the Swiss Guard posted outside a door at the Vatican, standing in precisely the same spot day after day, year after year.

The researchers said they were able to assemble more the 20,000 time lapses from the photos mined. Each time lapse is made up of more than 1,000 pictures. But not all of the videos were successful. Some were blurry in areas of significant activity, such as buildings that were constructed very quickly. Others showed a strange twilight effect when daytime and nighttime photos were mixed together. And in cases when almost the entire photographed landscape shifted over time, such as a moving glacier, the stabilizing algorithm had a tough time keeping a single vantage point.

Most of the photos came from landmarks in North America and Europe, since those areas are heavily photographed. Comparatively few came from Africa and South America. The team said each time lapse took about six hours to assemble on a single computer. They plan to release the project code to the public so others can create their own time lapses. As more and more photos are posted online, time lapses can reveal changes to natural and manmade landscapes in even greater detail, and over longer periods of time.

You've read  of  free articles. Subscribe to continue.
Real news can be honest, hopeful, credible, constructive.
What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world.

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.

QR Code to How Google researchers turned millions of Flickr images into time-lapse videos
Read this article in
https://www.csmonitor.com/Technology/2015/0518/How-Google-researchers-turned-millions-of-Flickr-images-into-time-lapse-videos
QR Code to Subscription page
Start your subscription today
https://www.csmonitor.com/subscribe