Polarimetry, Interferometry and Polarimetric Interferometry in Synthetic Aperture Remote Sensing

1. Introduction Both Optical and Radar Imaging have matured considerably, and the benefits of using one imaging modality over the other are discussed frequently. For example, 'Hyper-spectral Optical (FIR-VIS-FUV) Radiometric Imaging' is considered to become the exclusive remote sensing system of the twenty-first century, and thought to be superior to 'Ultra-wide-band Microwave (HF-UHF-SHF-EHF) SAR Imaging' Remote Sensing technology [2]. In either case, the inherent electromagnetic vector wave interaction processes are subjected to Maxwell's equations; and constrained by the carrier frequency and bandwidth, the amplitude, phase and polarization; the dispersive and polarization-dependent material constituents of the propagation medium as well as of the illuminated scattering surface, its geometry and structure, and its voluminous vegetative over-burden as well as its composite geological under-burden. However, in order to identify parameters describing voluminous scattering scenarios beyond the skin depth of the vegetation canopy, the entire amenable air/space-borne frequency regime from MF (100 KHz) to FUV (10 PHz) needs to be implemented in remote sensing [3]. This implies that we require both radar and optical imaging together with full scattering matrix acquisition capabilities-in order to recover fully the intricate scattering mechanisms and bio-mass assessment tasks-as will be discussed in the following.