Cityfit - High-Quality Urban Reconstruction by Fitting Shape Grammars to Image and derived Textured Point Clouds

Abstract

of the CityFit project is to reconstruct the facades of 80 % of the buildings in the city of Graz fully automatically. The challenge is to establish a complete workflow, ranging from acquisition of images and LIDAR data over 2D/3D feature detection and recognition to the generation of lean polygonal facade models. The desired detail level is to represent all significant facade elements larger than 50 cm by explicit polygonal geometry. All geometry shall also carry descriptive annotations (semantic enrichment). This paper presents an outline of the workflow, important design decisions, and the current state of the project. First results were obtained by case studies of facade analysis followed by manual reconstruction. This gave important hints how to structure grammars for automatic reconstruction. 1