** Next:** Conclusions
** Up:** Ji and Claerbout: Migration
** Previous:** Examples

In order to recover the correct amplitude after
datuming or migration, we can use the least-squares imaging
method introduced by Ji(1992) elsewhere in this report.
We use conjugate gradient algorithm.
Convergence was obtained in less than five iterations.
The right side of Figure shows
the datuming inversion result after five iterations.
Comparing with the datuming result on the left side
in Figure , we can see the wavefield
is almost the same as the modeled wavefield on the upper left side
in Figure .
The right side of Figure shows
the migration inversion result after five iterations of
the conjugate gradient algorithm.
Comparing with the migration result on the left side
in Figure , we can see the noise has been reduced
and the reflectors are more clearly imaged.
**datuminv2
**

Figure 10 Least squares datuming result for scheme 2.
Left : Datuming result by applying the conjugate operator
of the modeling
( the same as Figure (c) ).
Right : Optimized datuming result by conjugate gradient datuming ( after 10 iteration ).

**topomiginv
**

Figure 11 Least squares migration result for scheme 2.
Left : Migration result by applying the conjugate operator
for the modeling
( the same as Figure (d) ).
Right : Optimized migration result by conjugate
gradient migration ( after 10 iteration ).

** Next:** Conclusions
** Up:** Ji and Claerbout: Migration
** Previous:** Examples
Stanford Exploration Project

11/17/1997