Interferometric Synthetic Aperture Microscopy: Computed Imaging for Scanned Coherent Microscopy

Brynmor Davis,Stephen Boppart,P Carney,Daniel Marks,Tyler Ralston

doi:10.3390/s8063903

Brynmor Davis, Stephen Boppart + Show 3 more

Open Access

https://doi.org/10.3390/s8063903

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Journal: Sensors	Publication Date: Jun 11, 2008
Citations: 49	License type: CC BY 4.0

Affiliation: University of Illinois Urbana-Champaign

Abstract

Three-dimensional image formation in microscopy is greatly enhanced by the use of computed imaging techniques. In particular, Interferometric Synthetic Aperture Microscopy (ISAM) allows the removal of out-of-focus blur in broadband, coherent microscopy. Earlier methods, such as optical coherence tomography (OCT), utilize interferometric ranging, but do not apply computed imaging methods and therefore must scan the focal depth to acquire extended volumetric images. ISAM removes the need to scan the focus by allowing volumetric image reconstruction from data collected at a single focal depth. ISAM signal processing techniques are similar to the Fourier migration methods of seismology and the Fourier reconstruction methods of Synthetic Aperture Radar (SAR). In this article ISAM is described and the close ties between ISAM and SAR are explored. ISAM and a simple strip-map SAR system are placed in a common mathematical framework and compared to OCT and radar respectively. This article is intended to serve as a review of ISAM, and will be especially useful to readers with a background in SAR.

Highlights

Traditional sensing modalities such as X-ray projection imaging [1], nuclear magnetic resonance (NMR) spectroscopy [2, 3], radar [4] and focused optical imaging [5] rely primarily on physical instrumentation to form an image
In optical coherence tomography (OCT) and Interferometric Synthetic Aperture Microscopy (ISAM) the data are collected as a function of two spatial variables in order to image a three-dimensional volume, so that the detector ranges over ρ = [x, y, 0]T and the object may be imaged for r = [x, y, z]T
ISAM images are compared to those obtained using standard OCT methods

Summary

Introduction

Traditional sensing modalities such as X-ray projection imaging [1], nuclear magnetic resonance (NMR) spectroscopy [2, 3], radar [4] and focused optical imaging [5] rely primarily on physical instrumentation to form an image. In OCT and ISAM the data are collected as a function of two spatial variables in order to image a three-dimensional volume, so that the detector ranges over ρ = [x, y, 0]T and the object may be imaged for r = [x, y, z]T . Unlike SAR beams, ISAM fields include a region within the object that is in focus.

Results

Conclusion