New techniques for automated architectural reconstruction from photographs

We investigate a strategy for reconstructing of buildings from multiple (uncalibrated) images. In a similar manner to the Facade approach we first generate a coarse piecewise planar model of the principal scene planes and their delineations, and then use these facets to guide the search for indentations and protrusions such as windows and doors. However, unlike the Facade approach which involves manual selection and alignment of the geometric primitives, the strategy here is fully automatic. There are several points of novelty: first we demonstrate that the use of quite generic models together with particular scene constraints (the availability of several principal directions) is sufficiently powerful to enable successful reconstruction of the targeted scenes. Second, we develop and refine a technique for piecewise planar model fitting involving sweeping polygonal primitives, and assess the performance of this technique. Third, lines at infinity are constructed from image correspondences and used to sweep planes in the principal directions. The strategy is illustrated on several image triplets of College buildings. It is demonstrated that convincing texture mapped models are generated which include the main walls and roofs, together with inset windows and also protruding (dormer) roof windows.