Julien Flamant, CRAN - Univ. de Lorraine

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Julien Flamant from CRAN - Université de Lorraine will give a seminar entitled "Algebraic reconstruction strategies for polarimetric phase retrieval" on Monday, January 29, 2024 at 02:00 p.m. in Room Pierre Cotton.

Abstract : Phase retrieval problems are ubiquitous in imaging applications, such as crystallography, coherent diffraction imaging or ptychography, among others. Motivated by recent advances in vectorial ptychography, we propose a novel phase retrieval model called polarimetric phase retrieval that leverages the physics of polarization measurement in optics.
In this talk, I will first detail the uniqueness properties of this new model by unraveling equivalencies with a peculiar polynomial factorization problem. The latter will turn out to play a critical role, both regarding uniqueness of the problem and the design of algebraic reconstruction methods based on approximate greatest common divisor computations. In particular, these algebraic approaches provide a cheap and, numerically efficient alternative to usual iterative algorithms. To conclude, I will outline how these strategies can be extended to perform image reconstruction in vectorial CDI.

Biography : Julien Flamant is a CNRS research scientist with CRAN, Université de Lorraine, Nancy, France since 2019. He received his Ph.D. degree from Ecole Centrale de Lille, France, in 2018. His research interests include polarimetric imaging, bivariate signal processing, quaternion-valued signal processing, and applications to physical sciences.