Ever-thought what you could do with all those unwanted digital images which are in your camera when you return from holiday. Well a team at the University of Washington is taking thousands of holiday photos and using them to recreate 3D images of famous landmarks.
The team is using images on the photo-sharing website called Flickr and at a recent conference on computer vision in the US showed how it was possible to use these photos to create a virtual 3D model of landmarks, including Notre Dame Cathedral in Paris.
To make the 3D digital model, the researchers first downloads from the website photos of a landmark such as Notre Dame. This could be as many as 80,000 pictures.
After a sifting process, an image processing tool developed at the Washington team is used to calculate where each person was standing when he or she took the photo. By comparing two photos of the same object that were taken from slightly different perspectives, the software applies principles of computer vision to figure out the distance to each point.
"The general principle is very similar to how our eyes work," said lead author Michael Goesele, a former postdoctoral researcher at Washington who is now a professor at Technische Universität Darmstadt in Germany. "You get multiple views from different points of a scene, and then you find the same point in different views and infer from that the depth of the object."
In tests, a computer took less than two hours to make a 3D reconstruction of St. Peter's Basilica in Rome, using 151 photos taken by 50 different photographers.
A reconstruction of Notre Dame Cathedral used 206 images taken by 92 people.
The resolution of the 3D model mostly depends on the resolution of the original photos. "We don't quite get the accuracy of a laser scanner, but we're in the ballpark," said Steve Seitz, associate professor of computer science and engineering at Washington.
This also demonstrates the scale of the data accessing capabilities of the Internet. A website such as Flickr, for example, holds more than a billion photos and a search for a specific landmark such as Notre Dame Paris finds more than 80,000 files.
More about research incorporating online photo collections is at: http://grail.cs.washington.edu/projects/cpc/