FREQUENCY DOMAIN APPROACH TO TWO-DIMENSIONAL MIGRATION.

The approximation used for migration, which is an inverse scatter problem, consists in neglecting second order and multiple reflections and in lumping the whole space between the reflector and the source into an homogeneous medium characterized by an average acoustic velocity. Various ″linear filtering″ methods for this approximation of the migration, considering both their accuracy and their cost in terms of computing time, were compared. The three methods analyzed were: convolutional migration, frequency domain migration, and recursive filter migration. It is shown that each method descends from the propagation equation and has different advantages and disadvantages; in particular, it is shown that the frequency domain migration can be advantageous from the computing time viewpoint, taking into account its maximal precision.