Multiparameter inversion of a layer of vegetation canopy over rough surface from the system response function based on the mueller matrix solution of pulse echoes

Abstract

Under a polarized pulse wave incidence, the temporal Mueller matrix solution from vector radiative transfer (VRT) equation for a layer of nonspherical particles above randomly rough surface is constructed. The system response function based on the Mueller matrix solution is developed, which takes into account the scattering intensity matrix of the canopy, attenuation coefficient matrix through the canopy, scattering intensity matrix of underlying ground surface, and echoes time delay. This system response model preserves consistence with the Mueller matrix solution. To evaluate the system response function from the wave profiles of the received pulse echoes, an adaptive nonlinear estimation method (ALM) is proposed. When the pulse echoes are received, it yields the system response function, i.e., four system parameters. These system parameters are used to invert multiparameters of the vegetation canopy and underlying rough surface, which include the canopy depth, scatterers size, orientation, density and dielectric constant, and the surface roughness and dielectric constant. Numerical examples show good performance of our method as a tractable approach for multiparameters inversion. Potential application and some issues of multiparameters inversion are discussed. An envisaged sensor and platform for practical realization is proposed.Index Terms-Adaptive nonlinear estimation method (ALM), multiparameter inversion, polarimetric pulse echoes, system response function, vector radiative transfer (VRT).