Researchers from Computer Science & Engineering department at University of Washington created a fascinating computing project: building 3D cities from images on Flickr. The project’s name is Community Photo Collections and it gained a lot of fans in the industry, including Microsoft and its PhotoSynth project.

But even with commercial applications appearing on the map, researchers from the GRAIL Lab are continuing with their "Build a Rome in a Day" project. Long story short, this project takes large photo databases such as one on Flickr service and calculates common points inside those pictures. After the computation is done, an object or the complete city is rendered. The main pre-requisite for the project is that computation has to be done in a single day, e.g. 24 hours of computing time using their 496 CPU cluster.

Dubrovnik 3D fly-by built by using 58,000 pictures on Flickr
Dubrovnik 3D fly-by built by using 58,000 pictures on Flickr
 
Their latest creation is a flyby of City of Dubrovnik in my home country of Croatia. Dubrovnik has only 58,000 pictures on Flickr, but 352 CPUs crunched improved algorithms in 17 hours and 30 minutes and created a breath taking image of the old city core.

The Dubrovnik project was much more complex than previous Rome and Venice projects, since the limited picture gallery on Flickr contained greater differences in images. But after five hours of matching and 17.5 hours of calculation, a 39 second flyby was created. The visualization is available on YouTube in HD quality, and we definitely recommend you to visit the Building Rome in a Day website and see all of the reconstructions.

It is one impressive usage of computational power, that’s for sure.