There are three goals of the proposed approach. The first is to refine the 3D coordinates of the ground points of the buildings being assessed using the affine bias-compensated model that is shown to achieve the highest geopositioning accuracy in our experiment, the second is
to detect an individual collapsed building by comparing the height difference of the refined corner points of the building calculated from the pre- and post-seismic IKONOS stereo pairs, and the third is to determine the region of collapsed buildings by calculating the difference between the pre- and post-seismic DEMs generated again from the pre- and post-seismic stereo images with improved geopositioning accuracy.