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Imaging_fig
Figure 2 The geometry explication of the cross-correlation imaging condition. S^{*} is a virtual source of the real source S. The propagator L^{*} is the conjugate of the downward propagator L. Therefore, both the propagator L^{H} and L^{*} collapse the wavefronts into a point--the imaging point P. |
In the frequency domain, the extrapolated upcoming wavefield at the scattering point is
(36) |
(37) |
(38) |