When you think about all of the photos shared online, from holiday snaps on Facebook to a photographer's work on Flickr, it isn't all that surprising that there are zillions of digital photos in the public domain.
A team of scientists from Google and the University of Washington has recently created something pretty cool using these photos – a fully automated way of creating time-lapse videos of popular tourist landmarks. The images have come from popular photo-sharing websites, such as Flickr and Picasa.
So, how does it work? The researchers started by sorting an amazing 86 billion photos according to geographic location, looking specifically for widely snapped landmarks. Then, the photos were ordered by date and warped so that they all had a matching viewpoint. Finally, each photo was colour-corrected so that they have a similar appearance. The end result can be found in the video below.
The video isn't just amazing to watch, it also offers an illuminating look at the way our world has changed over the years. What is particularly of interest is the way our natural environment has changed – we see glaciers receding, waterfalls shrink to a trickle before growing once more, and the work done to some of the world’s biggest historical sites in order to restore them.
The science behind the time-lapses is also quite interesting – the researchers have combined various techniques in warping, stabilization and color normalizing in order to make the whole thing work. Many of the sequences contain over 1000 images and took around 6 hours to render.
And, even though these videos are a fun way to crowd source, they don't actually require participants to do anything more than simply be a tourist. With over 20,672 discovered time-lapses (and counting), which is your favourite?