Image-domain interferometry and wave-equation extended images

Using general two-and one-way representations for scattered wavefields, we fully describe two-and one-way extended images obtained in wave-equation imaging. This formulation explicitly connects the wavefield correlations done in seismic imaging with the theory and practice of wavefield interferometry. We show that extended images actually behave as local scattered fields in the image domain. The wavefield behavior of two-and one-way extended images is illustrated using analytical and numerical examples. The general description of extended images presented here may prove to be useful in further developing imaging and inversion methods.