Virtual cities from digital imagery

Increasing interest is being expressed in the use of virtual cities for many fields of application, ranging from planning and simulation to business. advertising and the games industry. Currently, the extraction of buildings from imagery is costly. However, recent developments in digital photogrammetry aim to produce more rapid and efficient methods of modelling three dimensional objects in urban environments. This paper presents a semi-automatic system for the extraction of buildings from digital aerial imagery with the aid of volumetric primitives. The user is supported by automated tools, for example matching tools, in order to reach the necessary efficiency. With an extraction time of about 20 s per building primitive, this method is competitive in terms of the performance of classical photogrammetric procedures, and also offers additional features for analysis, texture mapping and Internet applications.