A dual formulation for time-domain wavefield reconstruction inversion

TitleA dual formulation for time-domain wavefield reconstruction inversion
Publication TypeConference
Year of Publication2019
AuthorsGabrio Rizzuti, Mathias Louboutin, Rongrong Wang, Emmanouil Daskalakis, Felix J. Herrmann
Conference NameSIAM Conference on Mathematical & Computational Issues in the Geosciences

Wavefield reconstruction inversion (WRI) is based on the combination of data misfit and PDE-residual penalty terms, and it aims at the reconstruction of the optimal property model and field pair. A full-space optimization would require the storage of field variables for every frequency or time sample (and every source). Remedies via variable projection are well studied, but they entail the solution of a modified wave equation, which is costly both in frequency and time domain. Here, we explore an efficient alternative to WRI, where properties are complemented, instead, by elements of the dual data space. The starting point of our proposal is the denoising reformulation of WRI: the PDE compliance is optimized under the constraint of a given data fit. Since the field variable can be eliminated from the associated saddle-point problem, we obtain a new objective functional of only properties and Lagrange multipliers. Its evaluation, and gradient computation, involves the solution of the original wave equation, which is amenable to time-domain discretization. The optimization scheme of choice can now leverage on affordable storage of the iterates.





Citation Keyrizzuti2019SIAMGStwri