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Equation (1) exhibits a non-linear relationship between the laterally variable
slowness and the propagated wavefield. For the remaining of this paper, I will
conventionally refer to the methods in this class as non-linear methods. A second
class of methods are found using the Born approximation for the wavefield perturbations.
In physical terms, this approximation is only valid for media characterized by
weak scattering, that is small velocity variation.
Mathematically, the Born approximation is equivalent to a linearization of the
exponential . With this new approximation, the expression for the
downward-continued wavefield becomes:
| |
(6) |

Next two sections describe the various mixed-domain methods belonging to the two
aforementioned classes, linear and non-linear, in relation to the general
formula given by Equation (2).

** Next:** Non-linear migration methods
** Up:** Sava: Mixed-domain operators
** Previous:** Generalized screen
Stanford Exploration Project

9/5/2000