The propagative wavenumbers are carried by the First Fresnel zone of the velocity gradient of RFWI and diving-waves FWI. Noting that the parameter-dependent radiation patterns follow iso-angle curves, we compare the ellipse of the First Fresnel with the iso-angles curves. The latter are arcs of circles in homogeneous media. We show that the propagative part of the First Fresnel Zone can be precisely carved by a local angle filtering, more precisely that the implicit angle filtering carried by the velocity/impedance radiation pattern. For a given central frequency, the explicit angle filter requires only the knowledge of the local scattering angle and of the clock time of the wavefield snapshots.
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