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Extended PGA for Spotlight SAR-Filtered Backprojection Imagery

Shi, Tianyue ; Mao, Xinhua ; Jakobsson, Andreas LU orcid and Liu, Yanqi (2022) In IEEE Geoscience and Remote Sensing Letters 19.
Abstract

The phase gradient autofocus (PGA) is a robust autofocusing approach that can efficiently refocus defocused synthetic aperture radar (SAR) imagery produced by frequency-domain algorithms. However, from a conventional viewpoint, PGA cannot be extended to refocus SAR imagery produced by time-domain algorithms, such as the filtered backprojection (FBP), as the spectrum of the FBP imagery is range ambiguous and azimuth space-variant. In this letter, a novel interpretation of FBP is presented, in which the spectrum structure of the FBP imagery is analyzed in detail. By incorporating the derived spectral information, an efficient spectrum preprocessing is proposed for spectrum restructuring. After this preprocessing, PGA is shown to be able... (More)

The phase gradient autofocus (PGA) is a robust autofocusing approach that can efficiently refocus defocused synthetic aperture radar (SAR) imagery produced by frequency-domain algorithms. However, from a conventional viewpoint, PGA cannot be extended to refocus SAR imagery produced by time-domain algorithms, such as the filtered backprojection (FBP), as the spectrum of the FBP imagery is range ambiguous and azimuth space-variant. In this letter, a novel interpretation of FBP is presented, in which the spectrum structure of the FBP imagery is analyzed in detail. By incorporating the derived spectral information, an efficient spectrum preprocessing is proposed for spectrum restructuring. After this preprocessing, PGA is shown to be able to refocus defocused FBP imagery. The validity and feasibility of the proposed autofocusing approach are demonstrated using both simulated and experimental data.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Autofocusing, filtered backprojection (FBP), phase gradient autofocus (PGA), synthetic aperture radar (SAR)
in
IEEE Geoscience and Remote Sensing Letters
volume
19
article number
4516005
publisher
IEEE - Institute of Electrical and Electronics Engineers Inc.
external identifiers
  • scopus:85142813530
ISSN
1545-598X
DOI
10.1109/LGRS.2022.3223164
language
English
LU publication?
yes
id
99fa2cae-01d0-4d06-9c9f-320cb7022932
date added to LUP
2023-01-31 13:56:30
date last changed
2023-11-18 09:35:18
@article{99fa2cae-01d0-4d06-9c9f-320cb7022932,
  abstract     = {{<p>The phase gradient autofocus (PGA) is a robust autofocusing approach that can efficiently refocus defocused synthetic aperture radar (SAR) imagery produced by frequency-domain algorithms. However, from a conventional viewpoint, PGA cannot be extended to refocus SAR imagery produced by time-domain algorithms, such as the filtered backprojection (FBP), as the spectrum of the FBP imagery is range ambiguous and azimuth space-variant. In this letter, a novel interpretation of FBP is presented, in which the spectrum structure of the FBP imagery is analyzed in detail. By incorporating the derived spectral information, an efficient spectrum preprocessing is proposed for spectrum restructuring. After this preprocessing, PGA is shown to be able to refocus defocused FBP imagery. The validity and feasibility of the proposed autofocusing approach are demonstrated using both simulated and experimental data.</p>}},
  author       = {{Shi, Tianyue and Mao, Xinhua and Jakobsson, Andreas and Liu, Yanqi}},
  issn         = {{1545-598X}},
  keywords     = {{Autofocusing; filtered backprojection (FBP); phase gradient autofocus (PGA); synthetic aperture radar (SAR)}},
  language     = {{eng}},
  publisher    = {{IEEE - Institute of Electrical and Electronics Engineers Inc.}},
  series       = {{IEEE Geoscience and Remote Sensing Letters}},
  title        = {{Extended PGA for Spotlight SAR-Filtered Backprojection Imagery}},
  url          = {{http://dx.doi.org/10.1109/LGRS.2022.3223164}},
  doi          = {{10.1109/LGRS.2022.3223164}},
  volume       = {{19}},
  year         = {{2022}},
}