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SUMMARY:Linear and nonlinear inverse problems in imaging  -  Dr Leslie Gre
 engar\, New York University
DTSTART:20210528T130000Z
DTEND:20210528T140000Z
UID:TALK158899@talks.cam.ac.uk
CONTACT:Hilde Hambro
DESCRIPTION:Inverse problems arise routinely in imaging and structure dete
 rmination using a variety of experimental modalities. After an overview of
  numerical aspects of medical imaging\, we will consider inverse acoustic 
 scattering and protein structure determination from cryo-electron microsco
 py data (cryo-EM). These are computationally intensive tasks that are typi
 cally formulated as non-convex optimization problems. In cryo-EM\, the raw
  data is extremely noisy and existing methods are generally based on some 
 version of maximum likelihood estimation\, with a low resolution starting 
 guess. In inverse acoustic scattering\, the underlying physical problem is
  ill-posed and requires both regularization and high-order methods to solv
 e a sequence of forward scattering problems. We will present some algorith
 ms for accelerating image reconstruction in all these settings\, illustrat
 e their performance with several examples\, and discuss open problems in t
 he field.
LOCATION:Zoom Meeting ID: 867 5602 4340
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