Grammar-based 3D facade segmentation and reconstruction

Recent advances in scanning technologies allow large-scale scanning of urban scenes. Commonly, such acquisition incurs imperfections: large regions are missing, significant variation in sampling density, noise and outliers. Nevertheless, building facades often consist structural patterns and self-similarities of local geometric structures. Their highly structured nature, makes 3D facades amenable to model-based approaches and in particular to grammatical representations. We present an algorithm for reconstruction of 3D polygonal models from scanned urban facades. We cast the problem of 3D facade segmentation as an optimization problem of a sequence of derivation rules with respect to a given grammar. The key idea is to segment scanned facades using a set of specific grammar rules and a dictionary of basic shapes that regularize the problem space while still offering a flexible model. We utilize this segmentation for computing a consistent polygonal representation from extrusions. Our algorithm is evaluated on a set of complex scanned facades that demonstrate the (plausible) reconstruction.

Figure optionsDownload high-quality image (97 K)Download as PowerPoint slideHighlights
► Utilization of grammar rules as prior for segmenting and reconstructing scanned facades.
► Definition of a probability map to determine the relationship between elements of the grammar and the scanned data.
► The segmentation task is considered as an optimization problem of a sequence of derivation rules with respect to a given grammar.
► Outcome of this method is an accurate segmentation of the facade with basic elements that can be extruded to reconstruct the polygonal model.