The automatic creation of GIS-ready 3D city models and textured buildings from aerial images or Lidar is rapidly gaining importance across the industry as national mapping agencies and municipalities are seeking to convert their cadastre or base map from 2D to 3D to support better planning, taxation, civic engagement and the growing number of smart city applications.
For many years Leica Geosystems’ tridicon City Modeller has been among Europe’s leading solutions to automatically create textured 3D buildings from aerial data and existing building footprints with recognition accuracies greater 90%”, said Ruedi Wagner, vice president of Geospatial Solutions at Leica Geosystems. Unfortunately, the majority of the world’s countries lack accurate land information or existing building footprints. This combined with rapid urban change and regionally unique architecture styles have made the automated extraction of buildings from airborne images with similar accuracy and recognition rate a real challenge. With the new tridicon Building Finder Leica Geosystems has solved this challenge and customers in North America, South America or Asia are now able to automatically create highly accurate 3D City Models from airborne images without any prior knowledge.
City Mode
The new tridicon Building Finder with the new “City Mode” is based on a what Leica Goesystems calls revolutionary feature extraction approach that no longer relies on roof type libraries nor building footprints. To maximise the recognition rate and accuracy, customers can now select from various extraction strategies those that best fit their input data, built-up area density and the prevalent regional architectural styles such as shopping malls, inner city areas or suburban apartment blocks. Results can be further improved when combined with the Leica RCD30 oblique camera system.
The high quality of the Leica RCD30 oblique system supports the building extraction accuracy downstream, explained Peter Lieckfeldt, general manager for tridicon software. They use the high geometric accuracy of the Leica RCD30 and their own tridicon APMtrio software to triangulate nadir and oblique images together and generate highly accurate nadir and oblique pointclouds. The multispectral capability is used to classify and separate the vegetation in the pointcloud and to smartly select the building textures with the least amount of vegetation. Lastly, depending on input data, customers can now expand from the proven LOD2 buildings based on rooftypes, to more complex buildings based on building outline and meshed roof types, thus combining GIS-ready models with the visual accuracy of meshed surfaces.
Source: GIM International