Change Detection Using High Resolution Terrasar-x Data Preliminary Results

This paper presents preliminary results of change detection studies using TerraSAR-X spaceborne data. Change detection is important for a variety of applications like updating maps (several years following the creation of the base map), emergency assessment following a natural catastrophe, and site monitoring. The first two cases often rely on existing geospatial information (i.e. maps) in the area of interest and involves data from different sources. Site monitoring on the other hand includes the observation of ongoing changes. Time series using an active sensor with a short revisit rate are optimal for this task. The highresolution of TerraSAR-X and its short repeat cycle of eleven days allow reliable time series acquisitions. ACD (Amplitude Change Detection), an incoherent method, compares the backscatter of two images acquired using the same imaging parameters. It is sensitive to significant changes, i.e. changes that strongly influence the backscatter of an area. CCD (Coherence Change Detection) exploits the coherence of two SAR images acquired at different times using the same imaging parameters. They can be used to detect subtle changes occurring between the two observation dates that would remain undetected by incoherent change detection techniques. While CCD is more sensitive compared to ACD, its applicability is limited by vegetation cover. The combined use of ACD and CCD offers a more complete picture of any changes observed.