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Figure 5.18 ‘W-‐Filter’ tool
An example of the final result can be shown in the Figure 5.19:
Figure 5.19 Left: panchromatic image. Right: W-‐Filter output
Note: For more information about the algorithms included in BREC, see Gamba, P. Dell’Acqua, F. Lisini, G. (2009). BREC: The Built-‐up area RECognition tool. Joint Urban Remote Sensing Event, Shanghai, China. Damage Detection The procedure described in this section is used for damage detection when an earthquake happens. The idea is to apply a ‘Change detection’ method to the building footprints between the pre-‐ and post-‐event. The two images need to be co-‐registered within 1 or 2 pixels for the method to be effective. The change detection then simply generates a raster that is the difference between the PRE-‐ and POST-‐ images. Building Footprint Extraction (Pre-‐ and Post-‐Event) In this section the user has to extract the building footprints from the pre-‐event and the post-‐event image. The method is the same explained in this document under ‘Building footprints extraction’ section 5.1.1.