FPGA-based hardware acceleration of electromagnetic wave reverse time migration imaging

Abstract

Electromagnetic wave reverse time migration (RTM) imaging based on finite difference time domain (FDTD) method is widely used in geological exploration. It can accurately attribute the wavefield to its true subsurface spatial location when dealing with steeply dipping structures and complex velocity models. However, the forward and backward propagation processes of RTM imaging require recording wavefield information at each time step, which causes a large number of buffer accesses to degrade the overall calculation speed. This computationally and data intensive features limits its application in more scenarios. Therefore, this paper develops the FDTD prototype accelerator based on FPGA to accelerate the forward and backward propagation process of reverse time migration imaging, and realize the hardware circuit of cross-correlation imaging conditions. The experimental results show that the forward propagation process of FPGA at a clock frequency of 100MHz is 17.384 times faster than the PC using 3.6GHz CPU, and the backward propagation process is 18.371 times faster in comparison.