Flatness in
migrated angle-domain common image gathers is
an effective criterion for measuring migration-velocity accuracy.
An objective function that measures the power of the stack
as a function of residual-moveout parameters directly,
and indirectly as a function of migration velocity,
can be robustly maximized by using a gradient-based method.
This paper presents a method to compute the gradient of this
objective function by wave-equation operators.
The proposed algorithm has the additional advantage of not requiring
the picking of the residual-moveout parameters.
![[pdf]](icons/pdf.png){kind=icon}
) with respect to moveout parameters (
)
)