Date: December 9, 2005

Time: 3:00 p.m.

Location: Centergy One, Room 5186

Speaker(s): Kerkil Choi

Title: Iterative Methods for Phase Retrieval and X-ray Crystallography

Abstract:
Phase retrieval consists of reconstructing Fourier phases from only Fourier magnitudes. Despite the problem's simplicity, no method exists that can always solve this problem. Various methods have been proposed, and in this talk, a minimum I-divergence method for phase retrieval, which can be interpreted as a maximum-likelihood-estimation method, is briefly discussed.

X-ray crystallography is a phase retrieval problem with some specialness. The minimum I-divergence phase retrieval algorithm is proposed as a new starting point for x-ray crystallography. Several challenges that remain to be resolved for this application will be discussed.

Bio:
Kerkil Choi received his B.S. Degree in Electronic Engineering from Inha University, Incheon, Korea in 2000 and his M.S. Degree in Electrical and Computer Engineering from the University of Florida at Gainsville in 2002. His master's thesis focused on emission tomography. He plans to receive his Ph.D. Degree in Electrical and Computer Engineering from Georgia Institute of Technology in 2005. His main theoretical interests lie in the realm of statistical signal and image processing, with an emphasis on iterative reconstruction algorithms and regularization techniques. His applied interests include phase retrieval (particularly in x-ray crystallography) and linear inverse problems.

Slides: sem12_09_05_Kerkil_Choi.ppt

Date:	December 9, 2005
Time:	3:00 p.m.
Location:	Centergy One, Room 5186
Speaker(s):	Kerkil Choi
Title:	Iterative Methods for Phase Retrieval and X-ray Crystallography
Abstract:	Phase retrieval consists of reconstructing Fourier phases from only Fourier magnitudes. Despite the problem's simplicity, no method exists that can always solve this problem. Various methods have been proposed, and in this talk, a minimum I-divergence method for phase retrieval, which can be interpreted as a maximum-likelihood-estimation method, is briefly discussed. X-ray crystallography is a phase retrieval problem with some specialness. The minimum I-divergence phase retrieval algorithm is proposed as a new starting point for x-ray crystallography. Several challenges that remain to be resolved for this application will be discussed.
Bio:	Kerkil Choi received his B.S. Degree in Electronic Engineering from Inha University, Incheon, Korea in 2000 and his M.S. Degree in Electrical and Computer Engineering from the University of Florida at Gainsville in 2002. His master's thesis focused on emission tomography. He plans to receive his Ph.D. Degree in Electrical and Computer Engineering from Georgia Institute of Technology in 2005. His main theoretical interests lie in the realm of statistical signal and image processing, with an emphasis on iterative reconstruction algorithms and regularization techniques. His applied interests include phase retrieval (particularly in x-ray crystallography) and linear inverse problems.
Slides:	sem12_09_05_Kerkil_Choi.ppt