SC²S Colloquium - September 18, 2012
|Date:||September 18, 2012|
|Time:||2 pm, s.t.|
Philipp Braun: Probe function refinement in X-Ray Ptychography
Ptychography is an imaging technique that produces high-resolution quantitative maps through the combination of multiple coherent diffraction measurements from the illumination of several overlapping regions on the specimen. The lens optics of conventional imaging systems are replaced by an iterative algorithm in this technique. Experimental errors may produce deviations in the position of the X-ray illumination relative to the specimen and the topic of this thesis was to optimize the existing iterative algorithm to account for and optimize those subpixel displacements. This problem was solved with an Expectation Maximization approach and extensive simulations were done to test the quality improvement of the final image.