Location:	Rebecca's Cafe, 275 Grove St., Auburndale, MA 02466
Dinner Reservation Deadline:		May 11, 2015 @ 6pm

Compressive phase retrieval

Compressive sensing is a class of image recovery techniques utilizing sparsity priors to recover undersampled signals with high fidelity. This talk is about compressive sensing for phase retrieval from coherent fields and correlation function retrieval from partially coherent fields. For coherent fields, I will discuss in particular the use of intensity priors in the “transport of intensity equation” method, where the phase is obtained by analogy to a lateral pressure potential in a compressible flow. Transport of intensity is especially interesting in the x-ray regime, where standard interferometry is difficult because common sources are spatially partially coherent and beam splitters-combiners are not available; as a convincing example, I will show how the sparsity prior of quasi-constant object density allows successful x-ray phase recovery despite the low coherence. For partially coherent fields, I will describe how by using phase-space (Wigner space) methods and sparsity priors on the number of coherent modes it is possible to retrieve the correlation function, which can still lead to complete characterization of physical objects. 

MEETING SPONSORED BY

George Barbastathis, MIT

George Barbastathis received the Diploma in Electrical and Computer Engineering in 1993 from the National Technical University of Athens (Πολυτεχνείο) and the MSc and PhD degrees in Electrical Engineering in 1994 and 1997, respectively, from the California Institute of Technology (Caltech.) After post-doctoral work at the University of Illinois at Urbana-Champaign, he joined the faculty at MIT in 1999, where he is now Professor of Mechanical Engineering. He has worked or held visiting appointments at Harvard University, the Singapore-MIT Alliance for Research and Technology (SMART) Centre, the National University of Singapore, and the University of Michigan – Shanghai Jiao Tong University Joint Institute (密西根交大学院) in Shanghai, People’s Republic of China.

His research interests are three-dimensional and spectral imaging; phase estimation; holography; and gradient index optics theory and implementation with subwavelength-patterned dielectrics. He is member of the Institute of Electrical and Electronics Engineering (IEEE), the American Society of Mechanical Engineers (ASME) and in 2010 he was elected Fellow of the Optical Society of America.