CMRT09: Object Extraction for 3D City Models, Road Databases and Traffic Monitoring - Concepts, Algorithms, and Evaluation 
future. To not only compare the position of the peaks but also 
the shape of the reflection profile, the elevations of the 
simulated point scatterers (see Fig. 12) were fed into the 
tomographic analysis assuming the same imaging configuration 
as for the real TerraSAR-X data. As can be seen from Fig. 14, 
the profile matches very well with the tomographic results from 
real data (Fig. 13). This example provides a validation of the 
SAR simulator in the third dimension by comparing to the 
tomographic analysis result using the TerraSAR-X data. In a 
further step, it can also be used for validation of tomographic 
algorithms by simulating the complex valued measurements of 
a data stack with different baseline distributions. 4 
Figure 13: reflectivity function extracted from TerraSAR-X 
data by SAR-Tomography; intensity peaks estimated 
at heights of 3 m and 22.5 m 
Simulated tomographic profite from poor provided by SAR emulation 
Figure 14: reflectivity function estimated from simulated data 
extracted from simulator by SAR-Tomography. 
4. SUMMARY AND OUTLOOK 
In this paper, a concept and its prototype implementation for 3D 
analysis of reflection effects has been presented. 3D model 
scenes are sampled by ray tracing techniques for providing 
necessary output data in azimuth, slant-range and elevation. 
Elevation slices are determined by pixel selection in reflectivity 
maps in the azimuth-range plane. Comparison of simulated data 
with real SAR data for a selected urban scene provided 
promising results. Further studies will have to show whether 
simulated elevation data may also support the geometrical 
analysis of more complex 3D urban scenes since visual 
interpretation of the simulation results is expected to become 
more complicated due to the increased number of visible 
building features. Meanwhile, the SAR estimator will be 
extended for the purpose of validation of tomographic 
algorithms. 
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