Robust wave equation migration velocity analysis using a normalized differential semblance misfit function

The wave equation migration velocity analysis (WEMVA) techniques try to estimate an accurate subsurface velocity model for migration purposes by relying on the full-wave equation. A popular method in WEMVA is the differential semblance optimization (DSO). The objective function of DSO applies a penalty operator to extended subsurface images to minimize the energy residing in the non-physical extension. The penalty operator used in conventional DSO actually tries to reduce the energy instead of focussing it toward the subsurface zero offset. We introduce a normalization term to the DSO method in which we use a pseudo inverse Born operator to calculate the extended image and show that the new objective is more efficient and robust in focusing the energy and eliminating artifacts in the process of estimating the macro-velocity model.