Optimal Parameter Estimation of BSDF in SAR Simulation Based on Differential Ray Tracing

Simulation of Synthetic Aperture Radar (SAR) image in complex scenes has always been a challenging research. The key step of the simulation is determining the parameters of the bidirectional scattering distribution function (BSDF). However,the lack of BSDF parameters optimization make it difficult to get a good simulation. In this work, an optimal parameter estimation of BSDF based a differentiable ray-tracing is proposed. In this SAR image simulation engine, ray-tracing mapping and projection algorithm (MPA) can be inversely differentiable and thus gradient estimation of parameters can be quickly obtained from simulated SAR images. Additionally, with the help of robust physical scattering model based on small perturbation method (SPM) for microray tracing, a better BSDF is obtained, which improve the performance of SAR simulation.