For the converted-mode case, the angle axis of the final image
(), after the transformation, is neither
the incidence nor reflection angle, but the average of both.
The *full-aperture* angle gathers can be transformed into
two separate angle gathers, each one representing the incidence
and reflection angle. This transformations might bring useful
information for the analysis of rock properties or velocity updates
for the two different velocity models.

The transformation from SODCIGs into ADCIGs with a Fourier domain approach
is accurate only for constant velocity. The general transformation needs
to be done in the image space. Radon Transforms may provide to be a solution
for this situation. The method will use the information along both the
midpoint and subsurface offset axes in order to map the image
into the *full-aperture* angle axis.

The next step is to analyze how errors in either P or S velocity models are transformed in the PS-ADCIGs. This will result in both a formulation for the residual moveout of converted mode data, and a methodology for vertical velocity updates of both P and S velocity models.

5/3/2005