Detecting building facade damage from oblique aerial images using local symmetry feature and the Gini Index

The Classification of damaged building types is currently a relevant topic in disaster assessment and management, and the detection of damaged building facades is important to improve the classification accuracy. In this letter, a novel approach for automatic detection of damaged facade based on local symmetry features and the Gini Index using oblique aerial images is presented. First, local symmetry points are detected in a sliding window. Then, we obtain histogram bins of local symmetrical points in the vertical and horizontal directions. Finally, damaged and undamaged of building facades are distinguished using Gini Index. An evaluation of experimental result, for a selected Beichuan earthquake ruins study site, in Sichuan, China, shows that this method is feasible and effective for the detection of damaged facades.