Moving beyond the Born approximation involves one of the two
solutions: we can either artificially create image perturbations
that are compliant with this approximation Sava and Biondi (2001),
or we can improve the WEMVA operator to better handle the
non-linearity in the image perturbations, as presented in this
paper.
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We propose two improved versions of the WEMVA operator which are more appropriate for the case of large/strong slowness anomalies. Our new operators involve linearizations using bilinear and implicit approximations to the exponential function. With the new operators, we not only improve accuracy but we also maintain stability of the inversion scheme at much higher values of the slowness anomalies, even in the order of of the background.

Finally, we note that our new operators come at a cost which is practically no different than the cost of the Born-linearized operator, while improving its accuracy and stability.

6/7/2002