4.2. Detection results for an individual collapsed building Using the bias-compensated RPC model, the 3D ground coordinates of the corner points of a building, as calculated from the pre- and post-seismic IKONOS stereo pairs, are refined, and the collapsed building is detected by comparing the heights of the corner
points of the building before and after the earthquake. Fig. 7 shows eight detected buildings in the pre- and post-seismic images of the study area.