“…However, the time domain scattering data is a potential alternative scheme for the inverse problem, because there is more available information about the scatterer than for single-frequency scattering data alone. Therefore, various time domain inversion approaches have been intensively proposed in recent years, which could be briefly classified into the layer-stripping approach (Yagle & Frolik, 1996) and iterative approaches, including the Born iterative method (BIM; Moghaddam et al, 1991), the distorted Born iterative method (DBIM; Weedon, 1994), and optimization approaches (Rekanos, 2003;Takenaka et al, 2000;He et al, 1996).…”