chapter  15
34 Pages

SAR Images of Built-Up Areas: Models and Data Interpretation

WithGiorgio Franceschetti, Antonio Iodice, Daniele Riccio

CONTENTS 15.1 Introduction and Motivations............................................................. 298 15.2 SAR Image Model................................................................................. 299 15.3 Models for the Single Building Canonical Element

in the SAR Image .................................................................................. 301 15.4 Electromagnetic Methods to Evaluate the Backscattered Field .... 304

15.4.1 Scattering Methods ................................................................. 304 15.4.2 Kirchhoff Approximation ...................................................... 306 15.4.3 PO Solution .............................................................................. 307 15.4.4 GO Solution ............................................................................. 308

15.5 Single Return Contributions ............................................................... 308 15.5.1 Single Return from the Building’s Walls ............................ 309 15.5.2 Single Return from the Ground or from

the Building’s Roof ................................................................. 309 15.6 Double Return Contributions ............................................................. 311

15.6.1 Wall-Ground Return.............................................................. 311 15.6.2 Ground-Wall Return.............................................................. 313

15.7 Triple Return Contributions................................................................ 314 15.7.1 Wall-Ground-Wall Return.................................................... 314 15.7.2 Ground-Wall-Ground Return.............................................. 316

15.8 Numerical Examples ............................................................................ 316 15.9 Slant-Range Distribution of Canonical Scattering Solutions ......... 326 15.10 Comparison between Model Predictions and SAR Image

Appearance ............................................................................................ 328 References ........................................................................................................... 329

Monitoring of the urban environment is a key issue within the framework of modern and efficient management of Earth resources. Urban areas represent a very critical part of our planet due to the extremely high density of population and the continuous change of its environment. Spaceborne remote sensing instruments provide frequently updated and relatively inexpensive data to monitor and possibly plan urban area development and optimal resources distribution [1,2]. In particular, synthetic aperture radar (SAR) images provide all-day, all-weather, synoptic views whose potentiality has been only partly explored. Accordingly, electromagnetic models, aimed to quantitatively explore the information content in SAR images of urban areas, are required [3-5] to provide a sound analytical background to devise interpretation tools able to recover value-added information from the available SAR images [6-9].