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Title: A comparison of spotlight synthetic aperture radar image formation techniques

Abstract

Spotlight synthetic aperture radar images can be formed from the complex phase history data using two main techniques: (1) polar-to-cartesian interpolation followed by two-dimensional inverse Fourier transform (2DFFT), and (2) convolution backprojection (CBP). CBP has been widely used to reconstruct medical images in computer aided tomography, and only recently has been applied to form synthetic aperture radar imagery. It is alleged that CBP yields higher quality images because (1) all the Fourier data are used and (2) the polar formatted data is used directly to form a 2D Cartesian image and therefore 2D interpolation is not required. This report compares the quality of images formed by CBP and several modified versions of the 2DFFT method. We show from an image quality point of view that CBP is equivalent to first windowing the phase history data and then interpolating to an exscribed rectangle. From a mathematical perspective, we should expect this conclusion since the same Fourier data are used to form the SAR image. We next address the issue of parallel implementation of each algorithm. We dispute previous claims that CBP is more readily parallelizable than the 2DFFT method. Our conclusions are supported by comparing execution times between massively parallel implementationsmore » of both algorithms, showing that both experience similar decreases in computation time, but that CBP takes significantly longer to form an image.« less

Authors:
; ;
Publication Date:
Research Org.:
Sandia National Labs., Albuquerque, NM (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
399697
Report Number(s):
SAND-96-2460
ON: DE97000605; TRN: 96:006395
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Oct 1996
Country of Publication:
United States
Language:
English
Subject:
44 INSTRUMENTATION, INCLUDING NUCLEAR AND PARTICLE DETECTORS; 99 MATHEMATICS, COMPUTERS, INFORMATION SCIENCE, MANAGEMENT, LAW, MISCELLANEOUS; SYNTHETIC-APERTURE RADAR; IMAGES; ALGORITHMS; TOMOGRAPHY; FOURIER TRANSFORMATION

Citation Formats

Knittle, C.D., Doren, N.E., and Jakowatz, C.V. A comparison of spotlight synthetic aperture radar image formation techniques. United States: N. p., 1996. Web. doi:10.2172/399697.
Knittle, C.D., Doren, N.E., & Jakowatz, C.V. A comparison of spotlight synthetic aperture radar image formation techniques. United States. doi:10.2172/399697.
Knittle, C.D., Doren, N.E., and Jakowatz, C.V. Tue . "A comparison of spotlight synthetic aperture radar image formation techniques". United States. doi:10.2172/399697. https://www.osti.gov/servlets/purl/399697.
@article{osti_399697,
title = {A comparison of spotlight synthetic aperture radar image formation techniques},
author = {Knittle, C.D. and Doren, N.E. and Jakowatz, C.V.},
abstractNote = {Spotlight synthetic aperture radar images can be formed from the complex phase history data using two main techniques: (1) polar-to-cartesian interpolation followed by two-dimensional inverse Fourier transform (2DFFT), and (2) convolution backprojection (CBP). CBP has been widely used to reconstruct medical images in computer aided tomography, and only recently has been applied to form synthetic aperture radar imagery. It is alleged that CBP yields higher quality images because (1) all the Fourier data are used and (2) the polar formatted data is used directly to form a 2D Cartesian image and therefore 2D interpolation is not required. This report compares the quality of images formed by CBP and several modified versions of the 2DFFT method. We show from an image quality point of view that CBP is equivalent to first windowing the phase history data and then interpolating to an exscribed rectangle. From a mathematical perspective, we should expect this conclusion since the same Fourier data are used to form the SAR image. We next address the issue of parallel implementation of each algorithm. We dispute previous claims that CBP is more readily parallelizable than the 2DFFT method. Our conclusions are supported by comparing execution times between massively parallel implementations of both algorithms, showing that both experience similar decreases in computation time, but that CBP takes significantly longer to form an image.},
doi = {10.2172/399697},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Oct 01 00:00:00 EDT 1996},
month = {Tue Oct 01 00:00:00 EDT 1996}
}

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