Others working on the project are Brian Curless, a University of Washington associate professor of computer science and Microsoft researchers Hugues Hoppe and Richard Szeliski. Leading the 3-D mesh modeling was Michael Goesele, an assistant professor at Technical University Darmstadt in Germany.
Not only does the computer program have to match points, it has to figure out where the photographers were in relation to the building when they took the picture. It's a complex process, even for a computer or even groups of computers. Snavely explains that, "For a few hundred images, it tends to take a few days, for thousands of images it may take a few weeks."
Therefore, the engineers are still working on the program, looking for ways to make it faster and able to handle even more photographs.
Still, Seitz says the accuracy is, "pretty good… It's within about a quarter of a percent of what you would get with a laser scanner. A laser scanner is a very expensive piece of equipment to get very very accurate 3-D models in the field. This is kind of the benchmark for 3-D modeling. This is what the [special-] effects companies use."
While the 3-D modeling is their newest project and was presented for review at the 11th IEEE International Conference on Computer Vision, they have a second program called "Photo Tourism." The idea behind it is to organize online photos in a way so that they are linked visually. A viewer can start on a wide picture of someplace, and see optional views, angles and close-ups of that place, all taken by different photographers at different times and uploaded to different sites.
The program works best with exteriors of famous structures because they don't tend to change over time and people have uploaded many pictures. Seitz adds, however, "There's certainly cases where it doesn't work, and these are really the future research problems." He says those are "things like interiors with not much texture, things that are harder to match."
The researchers have some big goals for the software. Explains Seitz, "We'd like to be able to reconstruct a whole city. And, that will involve both operating on more photographs, but also generating and devising better algorithms that can process such photographs efficiently."
This research was presented for scientific review at the 11th IEEE International Conference on Computer Vision, October, 2007 in Rio de Janeiro, Brazil and was funded by The Alexander von Humboldt Foundation, the National Science Foundation, Microsoft Research and Adobe Systems Inc.