A Sinogram Decimation Fast Back-Projection Algorithm for Strip-Map SAR Imaging

• Published in: IEEE journal of selected topics in applied earth observations and remote sensing Vol. 18; pp. 6790 - 6805
• Main Authors: Xue, Zhiyuan, Li, Liang, Nan, Yijiang, Zou, Fei, Xu, Zongxiang, Yang, Tianyuan, Wang, Robert
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 2025; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Apertures; Back-projection (BP); Complexity theory; Computed tomography; Degradation; fast factorized back-projection (FFBP); Image reconstruction; Imaging; Radar imaging; Radar polarimetry; Remote sensing; SAR (radar); Spaceborne radar; Strip; strip-map imaging; Synthetic aperture radar; synthetic aperture radar (SAR); Tomography
• ISSN: 1939-1404; 2151-1535; 2151-1535
• DOI: 10.1109/JSTARS.2025.3544259

In this article, a novel sinogram decimation fast back-projection (SD-FBP) algorithm for strip-map synthetic aperture radar (SAR) imaging is proposed. We first review the back-projection (BP) and the fast factorized BP (FFBP) algorithms, then analyze the cause of the FFBP imaging degradation theoretically based on the combination of SAR imaging and the sinogram concept of computed tomography, illustrating that the degradation is much more severe for strip-map mode. Based on the SAR sinogram, the SD-FBP algorithm is proposed to mitigate the FFBP degradation for strip-map SAR imaging. The complexity of the SD-FBP is analyzed and compared with that of the FFBP and the Cartesian factorized BP (CFBP). The superiority of the SD-FBP algorithm is validated using the simulation and real spaceborne strip-map SAR data, e.g., Sentinel-1, Gaofen-3, and LuTan-1. The results show that the SD-FBP can tackle the FFBP imaging degradation for strip-map SAR, and runs faster than the FFBP and the CFBP.