Low-cost route to 3D scanning and model reconstruction

Paul Boughton
Constructing virtual 3D models usually requires heavy and expensive equipment or takes a long time. A group of researchers at the University of Cambridge Department of Engineering, namely Qi Pan, Dr Gerhard Reitmayr and Dr Tom Drummond, have created a program that is able to build 3D models of textured objects in real-time using only a standard computer and webcam. This makes 3D modelling accessible to everybody. The researchers presented the system at the 20th British Machine Vision Conference (BMVC'09), in London.
During the last few years many methods have been developed to build a realistic 3D model of a real object. Various types of equipment have been used: 2D/3D laser (in the visible spectrum or other wave lengths), scanner, projector, camera and others. These pieces of equipment are usually expensive, complicated to use or inconvenient, and the model is not built in real-time. The data (for example laser information or photos) must first be acquired before going through the lengthy reconstruction process to form the model. If the 3D reconstruction is unsatisfactory, then the data must be acquired again.
The method proposed by Qi Pan and his colleagues needs only a simple webcam. The object is moved about in front of the webcam and the software can reconstruct the object on-line 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 tetrahedralisation of the points (the extension of the 2D Delaunay triangulation to 3D). The points are recorded in a mesh of tetrahedra, within which is embedded the surface mesh of the object.
Lastly, the software can then tidy up the final reconstruction by taking out the invalid tetrahedra to obtain the surface mesh based on a probabilistic carving algorithm, and the object texture is applied to the 3D mesh in order to obtain a realistic model.
For more information, visit www.eng.cam.ac.uk

Recent Issues