Quality assessment of DEMs generated from interferometric SAR and stereo SAR

Rapidly evolution of the remote sensing technique is increasing by the developments of the satellite technology. Remote sensing technique has extensive applications that most of known are determination of health of the crops, soil moisture, forestry, water dirtiness, forest fire, oceanography, sea waves, meteorology, research of underground (subterranean) resources, desertification, investigation of the other planets, earthquakes, volcanic eruptions, landslides. Satellite images give wide information about the land structure that is useful and also manageable for generating true, high speed info generation, forecasting on future, environment and urban planning. Remote sensing has two systems that are active and passive systems. These systems used frequently because of covering large areas that is very handle to generate digital elevation model (DEM). Active systems which produce their own electromagnetic energy have some advantages. Capabilities of collecting data in nearly all atmospheric conditions, by day and/or night are the main properties of active systems. Destination of this research is accuracy assessments of DEMs that are generated from SAR Interferometry (InSAR) and Stereo SAR. For this application, horizontal (HH) polarized C band stereo SAR and InSAR RADARSAT images are used. DEMs that are generated bye stereo SAR and InSAR are compared. A DEM, which was generated from 1/25.000-scaled topographic maps, is used for the accuracy assessments. When generating DEM ground control points (GCP) are used and noticed that GCPs increases the accuracy of generated DEMs. Analyzes are estimated for three types of terrain, flat, slope and rough. Stereoscopic results denoted a min. standard deviation for flat areas is 5.58 m. and a max. is 12.09 m. Standard deviations for slope and rough areas are in order of min. 19.37 m., 42.45 m. and max. 27.30 m., 66.88 m. Interferometric analyzes mentioned just for slope and rough areas because interferometric DEM is failed due to low coherence. In interferometric results standard deviations of slope areas are min. 20.05 m., max. 31.81 m. and for rough areas are min. 37.81 m., max. 57.39 m. As a conclusion both stereo and interferometric methods showed that accuracy is decreased depending on increase of height. For this research it is evaluated that stereo method is better at flat areas and interferometric method is better for high areas. Key Words: Stereo SAR, SAR Interferometry, DEM, RADARSAT