Talk

Phase Retrieval: Computational Imaging in the Machine Learning Era

April 21, 2025
4:00 PM
B303, Electrical Engineering Department (second floor), IISc
phase retrieval computational imaging machine learning ptychography optical microscopy nonlinear inverse problems random matrix theory differentiable models

Speaker

Jonathan Dong
EPFL, Switzerland

Host

Prof. Chandra Sekhar Seelamantula

Abstract

Phase retrieval is a fundamental nonlinear inverse problem that appears across a wide range of computational imaging applications, from X-ray and electron ptychography to phase imaging in optical microscopy. Because it is often addressed through nonlinear optimization techniques, it has deep links with modern machine learning theory.

In this talk, I will provide a unified overview of phase retrieval models and algorithms, highlighting the connections between different applications. I will also discuss recent theoretical insights on reconstruction guarantees derived from random matrix theory. Finally, we’ll explore practical implementations, and I’ll share how these extend to our recent work on differentiable physical models and open-source computational imaging tools.

About the Speaker

Jonathan Dong is an SNF Ambizione Fellow with Prof. Michael Unser at the Biomedical Imaging Group, EPFL, Lausanne, Switzerland. He received his Ph.D. degree in Physics in 2020 from Ecole Normale Supérieure in Paris, France. His research interests include nonlinear inverse problems and computational imaging, with a focus on physics-based models, reconstruction algorithms, and statistical analysis methods.