Unified framework for modern synthetic aperture imaging algorithms

Abstract

Imaging using synthetic aperture techniques is a mature technique with a host of different reconstruction algorithms available. Often the same basic algorithm has a different name depending on where the particular algorithm is used, since it may have originated from the medical, nondestructive testing, geological, or remote sensing fields. All this adds to confusion for the nonspecialist. This article gives a short historical precise of active synthetic aperture imaging as it applies to airborne, spaceborne, and underwater remote sensing systems using either radar or sonar, then defines some generic imaging geometry and places all the usable synthetic aperture reconstruction algorithms in a unified framework. This is done by the introduction of mapping operators, which simplify the mapping or reformatting of data from one sampling grid to another. Using these operators, readers can see how strip-map synthetic aperture systems (both radar- and sonar-based) differ from spotlight synthetic aperture systems, how the various algorithms fit together, and how the chirp-scaling algorithm is likely to be the reconstruction algorithm of choice for most future strip-map systems, and just why that should be so. Multilook processing and methods to deal with undersampled apertures using postdetection digital spotlighting are put into the same unified framework, as both of these techniques are frequent adjuncts to synthetic aperture imaging. © 1997 John Wiley & Sons, Inc. Int J Imaging Syst Technol, 8, 343–358, 1997