Integrated method of building edge line feature extraction from aerial imagery and digital surface model

Rooftop edge line extraction is essential for building recognition and extraction in aerial images. In this paper, a new integrated edge line extraction algorithm is proposed for aerial imagery which often contains many buildings of complex shapes, and much more noise. Firstly, an improved marker-controlled watershed algorithm is applied to the aerial imagery segmentation, incorporated with altitude information of Digital Surface Model (DSM) to remove roads and shades. Meanwhile, the Canny operator is used to detect the edges of buildings. Then, for each building region obtained by segmentation, the new algorithm applies the line detection method based on phase-grouping to edge pixels. After edge lines are extracted initially, rooftop constraints are introduced in the rooftop main orientation counting procedure, which could help design and adjust lines. With all the procedures above, experiments show that the proposed method could achieve efficient and effective extraction of building edge line feature in aerial images.