IT abroad: Researchers create 3D models from online photo databases

Researchers from the University of North Carolina (UNC) and the Swiss university, ETH-Zurich have invented a technique that automatically creates 3D models of several world-known sights using millions of images available through Internet photo sharing sites.

Such a technique does already exist. It is called PhotoSynth and is being developed by Microsoft. Besides there is an alternative one created by the University of Washington (USA). However for conducting an analysis they need several powerful computers, whereas researchers from the UNC and the Swiss Federal Institute of Technology Zurich manage with a simple PC (though with 4 video cards). It took less than 24 hours.

The work was conducted in the following way. To reconstruct the model of the Colosseum the first task was to identify pictures on a website tagged with the word "Rome". A basic image analysis tool then created groups of photographs that have captured the same image - the west side of the Colosseum, for example. By analyzing how the object appeared from different viewing angles and distances, a rough 3D model of the object could be created. The researchers then used detailed analysis of each pixel within the group of photos to study the target object's surface.

As well as making eye-catching virtual models, the system can also highlight where tourists tend to congregate to snap the main attractions.