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Wouter van den Broek
(Thermo Fischer Scientific)

Lundi 28 mars 2022 à 14h00

Zoom link: https://univ-grenoble-alpes-fr.zoom.us/j/99178945783?pwd=eUtSa0k4K3lJeDNnZTUzL2JtMHl6UT09

ID de réunion : 991 7894 5783
Code secret : 291824

Title : « Overcoming information reduced data and experimentally uncertain parameters in ptychography with regularized optimization »

Abstract: The overdetermination of the mathematical problem underlying ptychography unfortunately is reduced by a host of settings that are experimentally more desirable. Furthermore, reconstruction of the sample-induced phase shift is typically limited by uncertainty in the experimental parameters, like beam position and shape, and finite sample thicknesses. Presented is a conjugate gradient descent algorithm, regularized optimization for ptychography (ROP), that recovers these partially known experimental parameters along with the phase shift, improves resolution by incorporating the multislice formalism to treat finite sample thicknesses, and includes regularization in the optimization process, thus achieving reliable results from noisy data with severely reduced and underdetermined information