IEEE Photonics Society

Boston Photonics Society Chapter

Boston Chapter of the IEEE Photonics Society

Imaging Workshop PDF

Wednesday, April 6, 13, 20, 28*, May 4, 2011, 7:00–9:30 PM (* Thursday April 28th)
Located at MIT Lincoln Laboratory – 244 Wood Street, Lexington, MA, 02420, USA

April 13, 2011
7 PM

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Synthetic Aperture Imaging Slides

Dr. Tyler S. Ralston, Lawrence Livermore National Laboratory, Livermore, CA


Dr. Tyler S. Ralston, Lawrence Livermore National Laboratory, Livermore, CA

Abstract:  Synthetic aperture imaging techniques are linked directly to the solutions of inverse scattering problems.   The talk will begin with the well-known synthetic aperture radar (SAR), a method for imaging with millimeter electromagnetic waves.  Concepts developed in radar are shown to apply to broadband optical imaging technologies.  Namely, interferometric synthetic aperture microscopy (ISAM) is a new computational technique for 3-D noninvasive biophotonic imaging. The hardware for ISAM is derived from the widely-used optical coherence tomography (OCT), a low-coherence interferometric (LCI) ranging technique with micron resolution deep (1-2 mm) within biological tissues. Both methods take advantage of the fact that the data are samples of a linear functional of the fields, and that the fields are connected to the object susceptibility function through Maxwell's equations. The susceptibility function, or a filtered version of it, is determined in terms of the known data by solving this system of equations. New advances in algorithms and computing hardware have enabled real-time ISAM – an important step toward enabling widespread clinical use.  Finally, the high-speed imaging techniques developed for ISAM are translated back to SAR to find application in a real-time radar imaging system.

Recommended Reading:

Introduction to Radar Systems, Merrill Skolnik

Spotlight Synthetic Aperture Radar: Signal Processing Algorithms, Walter G. Carrara, Ronald M. Majewski, Ron S. Goodman

Spotlight-mode synthetic aperture radar: a signal processing approach, Charles V. Jakowatz


Biography:  Tyler S. Ralston received his Bachelors degree in Electrical and Computer Engineering from the University of Dayton (2000). Prior to earning his Masters and PhD in Electrical and Computer Engineering from the University of Illinois (2006), he worked as an electrical engineer in the medical products industry at Battelle Memorial Institute (1998-2001). After his PhD, he worked as a post doctorate research scientist at the Beckman Institute (2006-2007) developing optical systems and algorithms for biomedical research applications. He then joined Massachusetts Institute of Technology Lincoln Laboratory (2007-2010) to develop algorithms for radar and optical systems. In 2010, he began working in his current position at Lawerence Livermore National Laboratory in the Adaptive Optics, and Signal/Image Processing Group.


For more information on the technical content of the workshop, contact either:
1) Farhad Hakimi (, Imaging Workshop Committee Co-Chair
2) William Nelson (, Imaging Workshop Committee Co-Chair
3) Reuel Swint (, Imaging Workshop Committee Co-Chair
4) Robert Stephenson (, Boston Photonics Society Chair