Creating 3-D models with a webcam

During the last few years, many methods have been developed to build a realistic 3-D model of a physical object, including 2-D/3-D lasers, scanners, projectors, and cameras. This equipment is usually expensive, complicated to use, or inconvenient, and the model is not built in real time.

Qi Pan, Gerhard Reitmayr, and Tom Drummond at the University of Cambridge (Cambridge, UK; www.cambridge.ac.uk) have created a program able to build 3-D models of textured objects in real time using only a standard computer and webcam. The object is moved about in front of the webcam and the software can reconstruct the object online while collecting live video.

The system uses points detected on the object to estimate object structure from the motion of the camera or the object, and then computes the Delaunay tetrahedralization of the points (the extension of the 2-D Delaunay triangulation to 3-D). The points are recorded in a mesh of tetrahedra, within which is embedded the surface mesh of the object.