A Layered Cross Correlation Back-Projection Algorithm Based on Ray-Theory for Electromagnetic Imaging in Stratified Medium

In this article, we present a layered cross correlation back-projection (LCBP) method based on ray-theory for electromagnetic (EM) imaging in stratified medium. To argue the challenge of resolving time delay in the stratified medium in traditional time-domain methods, we first construct a ray propagation model, then calculate the time delay at any point on the path and solve the sparse time delay at the deep position by linear interpolation, Finally, a clutter suppression method is used to reduce interference through the cross correlation of signals between different subapertures. LCBP achieves fast imaging in a stratified medium environment whereas retaining the advantages of the BP algorithm in the focusing ability. In order to verify the performance of the proposed method, the simulation and experimental data are carried out with comparisons of the phase shift migration (PSM) imaging method and layered range migration (LRM), and the proposed method exhibits excellent imaging quality.