2.3.2. Reverse Time Migration

Reverse time migration (RTM) is one of the best imaging methods for seismic data. RTM is a depth migration method. It takes the seismic records as input and reconstructs the underground wave field using the inverse time wave field continuation, then obtains the image amplitude according to the cross-correlation with the source wave field. There is no high-frequency approximation assumption of ray tracing methods or the angle limitation of one-way wave migration. Thus, RTM has a high imaging quality but also costs more in terms of computational resources.

RTM was adopted as a related work in this paper. The adopted reverse time migration program involved was from the authors of [30]. The algorithm dose is a prestack reverse time migration of a shot record. The migration computes the forward-in-time propagation of the source field and the reverse-time propagation of the input shot (receiver field). Thus, two wavefields (source field and receiver field) are simulated by finite-difference time stepping. The migrated shot comes from the cross correlation of these two fields at equal times. This requires that the source wavefield must be available at each time step of the receiver field and this is a major complexity.
