@TechReport{TR003,
  author =	 "Walter G. Kropatsch",
  institution =	 "PRIP, TU Wien",
  number =	 "PRIP-TR-003",
  title =	 "Integration of {SAR} and {DEM} Data - {G}eometrical
                  {C}onsiderations",
  year =	 "1992",
  url =		 "https://www.prip.tuwien.ac.at/pripfiles/trs/tr3.pdf",
  abstract =	 "General principles for integrating data from
                  different sources are derived from the experience of
                  registration of SAR images with DEM data. The
                  integration in our case consists of establishing
                  geometrical relations between the data sets that
                  allow to accumulate information from both data sets
                  for any given object point (e.g. elevation, slope,
                  backscatter of ground cover, etc.). Since the
                  geometries of the two data are completely different
                  they cannot be compared on a pixel by pixel
                  basis. The presented approach detects instances of
                  higher level features in both data sets
                  independently and performs the matching at the high
                  level. Besides the efficiency of this general
                  strategy it further allows the integration of
                  additional knowledge sources: world knowledge and
                  sensor charateristics are also useful sources of
                  information. The SAR features layover and shadow can
                  be detected easily in SAR images. An analytical
                  method to find such regions also in a DEM needs in
                  addition the parameters of the flight path of the
                  SAR sensor and the range projection model. The
                  generation of the SAR layover and shadow maps is
                  summarized and new extensions to this method are
                  proposed.",
}