H.: Irregular lattices for complex shape grammar facade parsing

High-quality urban reconstruction requires more than multi-view reconstruction and local optimization. The structure of facades depends on the general layout, which has to be optimized globally. Shape grammars are an estab-lished method to express hierarchical spatial relationships, and are therefore suited as representing constraints for se-mantic facade interpretation. Usually inference uses nu-merical approximations, or hard-coded grammar schemes. Existing methods inspired by classical grammar parsing are not applicable on real-world images due to their pro-hibitively high complexity. This work provides feasible generic facade reconstruction by combining low-level clas-sifiers with mid-level object detectors to infer an irregular lattice. The irregular lattice preserves the logical structure of the facade while reducing the search space to a manage-able size. We introduce a novel method for handling sym-metry and repetition within the generic grammar. We show competitive results on two datasets, namely the Paris2010 and the Graz50. The former includes only Hausmannian, while the latter includes Classicism, Biedermeier, Histori-cism, Art Nouveau and post-modern architectural styles. 1