A Novel Multistage Back Projection Fast Imaging Algorithm for Terahertz Video Synthetic Aperture Radar

Terahertz video synthetic aperture radar (THz-ViSAR) has tremendous research and application value due to its high resolution and high frame rate imaging benefits. However, it requires more efficient imaging algorithms. Thus, a novel multistage back projection fast imaging algorithm for the THz-ViSAR system is proposed in this paper to enable continuous playback of images like video. The radar echo data of the entire aperture is first divided into multiple sub-apertures, as with the fast-factorized back projection algorithm (FFBP). However, there are two improvements in sub-aperture imaging. On the one hand, the back projection algorithm (BPA) is replaced by the polar format algorithm (PFA) to improve the sub-aperture imaging efficiency. The imaging process, on the other hand, uses the global Cartesian coordinate system rather than the local polar coordinate system, and the wavenumber domain data of the full aperture are obtained step by step through simple splicing and fusion, avoiding the amount of two-dimensional (2D) interpolation operations required for local polar coordinate system transformation in FFBP. Finally, 2D interpolation for full-resolution images is carried out to image the ground object targets in the same coordinate system due to the geometric distortion caused by linear phase error (LPE) and the mismatch of coordinate systems in different imaging frames. The simulation experiments of point targets and surface targets both verify the effectiveness and superiority of the proposed algorithm. Under the same conditions, the running time of the proposed algorithm is only about 6% of FFBP, while the imaging quality is guaranteed.

[1]  Yihang Zhou,et al.  Joint autofocus and registration for video-SAR by using sub-aperture point cloud , 2023, Int. J. Appl. Earth Obs. Geoinformation.

[2]  Yun Lin,et al.  Video SAR Moving Target Shadow Detection Based on Intensity Information and Neighborhood Similarity , 2023, Remote. Sens..

[3]  Pei Wang,et al.  Generation of Multiple Frames for High Resolution Video SAR Based on Time Frequency Sub-Aperture Technique , 2023, Remote. Sens..

[4]  M. Xing,et al.  Sparse Synthetic Aperture Radar Imaging From Compressed Sensing and Machine Learning: Theories, applications, and trends , 2022, IEEE Geoscience and Remote Sensing Magazine.

[5]  Yiming Zhu,et al.  A High-Frequency Vibration Error Compensation Method for Terahertz SAR Imaging Based on Short-Time Fourier Transform , 2021, Applied Sciences.

[6]  Baojun Zhao,et al.  Robust Shadow Tracking for Video SAR , 2021, IEEE Geoscience and Remote Sensing Letters.

[7]  Li Ding,et al.  A Novel High-Frequency Vibration Error Estimation and Compensation Algorithm for THz-SAR Imaging Based on Local FrFT , 2020, Sensors.

[8]  Jianyu Yang,et al.  Video SAR Imaging Based on Low-Rank Tensor Recovery , 2020, IEEE Transactions on Neural Networks and Learning Systems.

[9]  Jin Li,et al.  Unified Coordinate System Algorithm for Terahertz Video-SAR Image Formation , 2018, IEEE Transactions on Terahertz Science and Technology.

[10]  Lei Zhang,et al.  Application of fast factorized back-projection algorithm for high-resolution highly squinted airborne SAR imaging , 2017, Science China Information Sciences.

[11]  Guoan Bi,et al.  Spectrum-Oriented FFBP Algorithm in Quasi-Polar Grid for SAR Imaging on Maneuvering Platform , 2017, IEEE Geoscience and Remote Sensing Letters.

[12]  Hui Xiao,et al.  Fast Factorized Backprojection Algorithm for One-Stationary Bistatic Spotlight Circular SAR Image Formation , 2017, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing.

[13]  Weidong Yu,et al.  Processing video-SAR data with the fast backprojection method , 2016, IEEE Transactions on Aerospace and Electronic Systems.

[14]  H. B. Wallace,et al.  Development of a video SAR for FMV through clouds , 2015, Defense + Security Symposium.

[15]  Z. Bao,et al.  A coordinate-transform based FFBP algorithm for high-resolution spotlight SAR imaging , 2015, Science China Information Sciences.

[16]  Zhiwei Xu,et al.  A Fast BP Algorithm With Wavenumber Spectrum Fusion for High-Resolution Spotlight SAR Imaging , 2014, IEEE Geoscience and Remote Sensing Letters.

[17]  M. Xiang,et al.  Joint Three-dimensional Location Algorithm for Airborne Interferometric SAR System: Joint Three-dimensional Location Algorithm for Airborne Interferometric SAR System , 2013 .

[18]  Armin W. Doerry,et al.  An application of backprojection for video SAR image formation exploiting a subaperature circular shift register , 2013, Defense, Security, and Sensing.

[19]  Cameron Musgrove,et al.  Polar format algorithm : survey of assumptions and approximations. , 2012 .

[20]  Gerhard Krieger,et al.  Efficient Time-Domain Image Formation with Precise Topography Accommodation for General Bistatic SAR Configurations , 2011, IEEE Transactions on Aerospace and Electronic Systems.

[21]  Wendy L. Garber,et al.  Extensions to polar formatting with spatially variant post-filtering , 2011, Defense + Commercial Sensing.

[22]  LeRoy A. Gorham,et al.  SAR image formation toolbox for MATLAB , 2010, Defense + Commercial Sensing.

[23]  Mengdao Xing,et al.  The Polar Format Imaging Algorithm Based on Double Chirp-Z Transforms , 2008, IEEE Geoscience and Remote Sensing Letters.

[24]  Charles V. Jakowatz,et al.  An implementation of a fast backprojection image formation algorithm for spotlight-mode SAR , 2008, SPIE Defense + Commercial Sensing.

[25]  R. N. Anderton,et al.  Millimeter-Wave and Submillimeter-Wave Imaging for Security and Surveillance , 2007, Proceedings of the IEEE.

[26]  Juan M. Lopez-Sanchez,et al.  Efficient Interpolation of SAR Images for Coregistration in SAR Interferometry , 2007, IEEE Geoscience and Remote Sensing Letters.

[27]  Daiyin Zhu,et al.  Range Resampling in the Polar Format Algorithm for Spotlight SAR Image Formation Using the Chirp $z$ -Transform , 2007, IEEE Transactions on Signal Processing.

[28]  Masayoshi Tonouchi,et al.  Cutting-edge terahertz technology , 2007 .

[29]  P. Frolind,et al.  Evaluation of angular interpolation kernels in fast back-projection SAR processing , 2006 .

[30]  Peter E. Buxa,et al.  Implementation and analysis of a fast backprojection algorithm , 2006, SPIE Defense + Commercial Sensing.

[31]  R. Moses,et al.  Taylor expansion of the differential range for monostatic SAR , 2005, IEEE Transactions on Aerospace and Electronic Systems.

[32]  Lars M. H. Ulander,et al.  Synthetic-aperture radar processing using fast factorized back-projection , 2003 .

[33]  Yoram Bresler,et al.  O(N2log2N) filtered backprojection reconstruction algorithm for tomography , 2000, IEEE Trans. Image Process..

[34]  Charles V. Jakowatz,et al.  Space-variant filtering for correction of wavefront curvature effects in spotlight-mode SAR imagery formed via polar formatting , 1997, Defense, Security, and Sensing.

[35]  Kah Chan Teh,et al.  Joint Low-Rank and Sparse Tensors Recovery for Video Synthetic Aperture Radar Imaging , 2022, IEEE Transactions on Geoscience and Remote Sensing.

[36]  Li Ding,et al.  Estimation of High-Frequency Vibration Parameters for Terahertz SAR Imaging Based on FrFT With Combination of QML and RANSAC , 2021, IEEE Access.

[37]  Majid Moradikia,et al.  Video-SAR Imaging of Dynamic Scenes Using Low-Rank and Sparse Decomposition , 2021, IEEE Transactions on Computational Imaging.

[38]  Armin W. Doerry,et al.  Wavefront curvature limitations and compensation to polar format processing for synthetic aperture radar images. , 2006 .

[39]  Richard Bamler,et al.  Evaluation of interpolation kernels for SAR interferometry , 1999, IEEE Trans. Geosci. Remote. Sens..

[40]  Giorgio Franceschetti,et al.  SARAS: a synthetic aperture radar (SAR) raw signal simulator , 1992, IEEE Trans. Geosci. Remote. Sens..

[41]  N. Hamano,et al.  Digital processing of synthetic aperture radar data , 1984 .