GENERATION AND ANALYSIS OF DIGITAL SURFACE MODELS (DSMS) IN URBAN AREAS BASED ON DMC-IMAGES

DSMs are a geometric description of the height of the visible terrain surface, including elements like buildings and trees. DSMs became an important source for scene analysis and for 3D feature detection and reconstruction. The digital metric camera (DMC) offers excellent image quality and can be used for automated DSM generation, with high accuracy. By using least squares matching as method to find corresponding points in two overlapping images for three dimensional reconstructions, the corresponding points potentially can be determined with sub-pixel accuracy. The investigation of the influence of different parameters on generating DSMs from DMC images is shown like the limitation of automatic DSM generation in urban areas. The aim of our investigation is, whether the selected parameters for image matching, optimized in few test areas, can be used for the whole study area. The generated DSM was checked against a reference DSM based on manual measurement. The comparison shows that the accuracy mainly depends on terrain slope and surface structure. Furthermore, satisfying DSMs strongly depend upon the quality of the DMC-images. A standard deviation of the DSM based on DMC-images in whole urban study area of 1.0 up to 1.3 GSD is possible, corresponding to 0.3 up to 0.4 GSD for the x-parallax