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We have shown that the minimum-phase helical factorization of the
Helmholtz equation can be applied recursively to extrapolate waves up
to 90. The hope is that a recursive extrapolator may image
steeper dips than an explicit extrapolator with the same cost.
Unfortunately, however, technical problems related to
the factoring of functions with roots near the unit circle, are
currently preventing this method from competing effectively with
conventional extrapolation algorithms.

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Stanford Exploration Project

7/5/1998