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SUMMARY:Wave-equation based inversion with constraints - Felix J. Herrmann
  (UBC–Seismic Laboratory for Imaging and Modelling)
DTSTART:20160421T140000Z
DTEND:20160421T150000Z
UID:TALK64798@talks.cam.ac.uk
CONTACT:Carola-Bibiane Schoenlieb
DESCRIPTION:While the advent of fast compute is making wave-equation based
  imaging & inversion a reality\, many challenges remain making. By means o
 f examples in linearized imaging and nonlinear full-waveform inversion\, w
 e will demonstrate how certain structure-promoting constraints can be used
  to speed up the calculations and to mitigate adverse affects of local min
 ima. More specifically\, we will show that for problems that involve the i
 nversion of expensive to evaluate Jacobians\, linearized Bregman iteration
 s\, which solve problems with mixed l1-l2 objectives\, continue to make pr
 ogress under randomized subsampling whereas standard (projected) gradients
  do not. We will also discuss how the adverse affects of local minima in f
 ull-waveform inversion can be overcome via structure-promoting constraints
 . In particular\, we review the advantages of working with multiple “sim
 ple” constraints instead of with penalties as is more commonly done.
LOCATION:MR 14\, CMS
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