  The quantitative reconstruction of sub-surface Earth properties from the
propagation of waves follows an iterative minimization of a misfit functional.
In marine seismic exploration, the observed data usually consist of
measurements of the pressure field but dual-sensor devices also provide the
normal velocity. Consequently, a reciprocity-based misfit functional is
specifically designed, and defines the Full Reciprocity-gap Waveform Inversion
(FRgWI ) method. This misfit functional provides additional features compared
to the more traditional least-squares approaches with, in particular, that the
observational and computational acquisitions can be different. Therefore, the
positions and wavelets of the sources from which the measurements are acquired
are not needed in the reconstruction procedure and, in fact, the numerical
acquisition (for the simulations) can be arbitrarily chosen. Based on
three-dimensional experiments, FRgWI is shown to behave better than Full
Waveform Inversion (FWI) in the same context. Then, it allows for arbitrary
numerical acquisitions in two ways: when few measurements are given, a dense
numerical acquisition (compared to the observational one) can be used to
compensate. On the other hand, with a dense observational acquisition, a sparse
computational one is shown to be sufficient, for instance with multiple-point
sources, hence reducing the numerical cost. FRgWI displays accurate
reconstructions in both situations and appears more robust with respect to
cross-talk than the least-squares shot-stacking.
