Time-shift imaging condition for converted waves

Algorithms

In the most general case described in this paper, a seismic image is a multi-dimensional object function of position ${ \bf m}$, space-shift ${ \bf h}$ and time-shift ${\tau}$, ${ \bf R}({ \bf m},{ \bf h},{\tau})$. We can use the relations between space and time coordinates developed in the preceding section to define various angle-decomposition algorithms. Since ${ \bf R}({ \bf m},{ \bf h},{\tau})$ is a large object that is unlikely, in practice, to be computed or stored completely, we design algorithms involving subsets of this large image: