Conclusions

This chapter presents a method for computing angle-domain common image gathers from wave-equation depth-migrated images. I produce angle gathers from migrated images with a process which is completely detached from migration. The output of this image-space method is a function of reflection angle, and not function of offset ray-parameter.

I show that this method is, in essence, a radial trace transform in the Fourier domain, and therefore equivalent to a slant stack in the space domain. The method is fully applicable to arbitrary models, with high image complexity and lateral velocity variations.

I implement the method using a stretch technique with model regularization, thus reducing the artifacts caused by non-uniform sampling due to the Fourier-domain radial-trace transforms. The method is accurate, fast, robust, easy to implement, and can be used for real prestack data for simple imaging or in applications related to migration velocity analysis (MVA) and amplitude versus angle (AVA) analysis.

Extensions to 3D are presented by (12), (13) and (36).