Automatic Road Extraction in Rural Areas

An approach for the automatic extraction of roads from digital aerial imagery is proposed. It is optimized for rural areas and makes use of versions of an aerial image with different resolutions. Roads are modeled as a network of intersections and links between these intersections, and are found by a grouping process. The context of roads is hierarchically structured into a global and a local level. At first, edges are extracted in the original high resolution image (0.2–0.5m) and lines in an image of reduced resolution (2 m). Using both resolution levels and explicit knowledge about roads, hypotheses for road segments are generated. They are grouped iteratively into larger segments. In addition to the grouping algorithms, knowledge about the local context, e.g., shadows cast by a tree onto a road segment, is used to bridge gaps. To construct the road network, finally intersections are extracted. Examples and results are given, indicating the potential of the approach.