One of the most interesting sessions at the recent SIGGRAPH 2009 conference was titled “Next Billion Cameras.”

More than a billion image sensors are manufactured each year with the majority going to digital cameras and mobile phone cameras. What are the implications of a billion cameras snapping photos around the world? Have the millions of online photos become a new data source that could be used in instructive or creative ways?

Alexei (Alyosha) Efros, assistant professor at the Robotics Institute and computer science department at Carnegie Mellon University, demonstrated how photos stored on Flickr and the other hosting services could be used to construct three-dimensional models of well-known tourist attractions, such as the Pantheon in Rome.

He also showed how an obstructed view, such as a landscape blocked by a building, could be repaired automatically using fill-in sections from a context-matched shot available online. The result becomes a seamless, idealized version of the original photo.