Flickr Generates Virtual Cities
Last year, Microsoft released its Photosynth application, which allows users to build 3D environments based on their photo libraries. Now, computer scientists at the University of Washington’s Graphics and Imaging Laboratory have one upped Photosynth by using the same imaging algorithms to create full, virtual cities of Venice, Rome and the Croation city of Dubrovnik, by analyzing thousands of photos posted on Flickr.
The same labs created the algorithms for the Photosynth software, but have now been drastically enhanced to take pools of photos ranging up to the 100’s of thousands to map and rebuild the environments.
The team built a new algorithm that proceeds in two steps — first, by matching the photos by what they had in common, puzzle-style, and then by determining the scene and each photographer’s pose. They also designed new software that can more quickly solve the type of large math problems that exist in 3-D reconstruction.
It took 500 computer processors 13 hours to match 150,000 photos for Rome’s landmarks, and eight more hours to construct a 3-D image of them. Venice involved 250,000 images, which took 27 hours to match and 38 hours to reconstruct. By contrast, using the algorithms on which Photosynth is based, it would have taken 500 processors at least a year to match 250,000 photos.
The only thing left now is to find a way to translate all this rich data into formats that can be read by 3D animators and modelers.