Low-rank-assisted inverse medium scattering: Lipschiz stability and ensemble Kalman filter
This work addresses inverse scattering problems in computational physics, offering a novel theoretical and numerical approach that is incremental in combining low-rank structures with ensemble Kalman filters.
The paper tackles the inverse medium scattering problem beyond the Born region by establishing Lipschitz stability for unknowns in a low-rank space and proposing a low-rank-assisted ensemble Kalman filter method, with numerical examples demonstrating feasibility.
In this work we study the theoretical Lipschitz stability and propose a low-rank-assisted numerical method for the inverse medium scattering beyond the Born region. The proposed low-rank structure is based on the disk prolate spheroidal wave functions, which are eigenfunctions of both the Born forward operator and a Sturm-Liouville differential operator. We obtain Lipschitz stability for unknowns in a low-rank space in the fully nonlinear case and characterize the explicit Lipschitz constant in the linearized region. We further propose an ensemble Kalman filter to iteratively update the unknown in the proposed low-rank space whose dimension is intrinsically determined by the wave number. Moreover the ensembles are sampled according to a novel trace class covariance operator motivated by the connection between the proposed low-rank space and the Sturm-Liouville differential operator. Finally numerical examples are provided to illustrate the feasibility of the proposed method.