Diagonal weighting functions for recursive prestack depth migration

In this Chapter, I compute diagonal preconditioning operators (weighting functions) appropriate for least-squares recursive depth migration. Only considering the main diagonal of ${\bf A}' \,{\bf A}$ simplifies matters significantly: the factorization itself reduces to taking a square root, and inverting the factors reduces to simple division. The only potential pitfall comes with division by zero.

As well as looking at model-space weights, I also consider data-space weighting functions derived from the operator ${\bf A}\, {\bf A}'$,and develop a framework for computing and applying both model and data-space weights simultaneously.