Understanding the Correlation in Scattering Mechanisms Between H-Alpha Decomposition and Theoretical Modelling

Synthetic Aperture Radar (SAR) is a space-borne or airborne side-look radar system that transmits electromagnetic waves and receives the returns from earth terrain. The classification of SAR images requires the understanding of the physical aspects of the interaction of microwave with different types of terrain cover. This paper discusses the usage of theoretical model simulation to study the wave interaction with different terrain cover as well as the expected backscatter results. This also provides an understanding of the dominant scattering mechanisms involved and provides further physical insight in classifying SAR images. In addition to this, a study of the correlation of these theoretical results based on basic scattering mechanisms is conducted with the associated scattering mechanisms indicated in the
$H$
-Alpha Decomposition which is a method commonly used in SAR image classification. The theoretical microwave scattering model of the scatterers is simulated with the solution of radiative transfer theory where the terrain is represented by a discrete medium embedded with scatterers of shapes such as cylinder, disk, needle or sphere. The influence of other physical parameters is also included in the study as well such as the scatterers dielectric constant, volume fraction, layer height and orientations. The simulation parameters are obtained from ground truth measurements in different terrains as reported in the literature. Different simulation cases are done for each case of terrain cover type. The simulation backscatter results are used as training parameters to study the decision boundaries for each terrain class in the feature space of
$H$
-Alpha Decomposition. Thus, an improved classification scheme based on better understanding of SAR microwave interaction with different terrain can be developed in future for better classification results of SAR images.