快速分级后投影(Fast Factorized Back Projection, FFBP)算法大幅减少了原始后投影算法的插值次数，提升运算效率。然而图像合成过程中仍然需要大量的图像域2维插值操作，庞大的计算量限制了其在实际中的应用。该文提出一种基于几何校正的聚束SAR快速分级后投影算法。该算法利用几何校正的方法实现子图像配准，即在满足聚焦性能的前提下，通过距离维平移和角度维旋转完成子图像在不同坐标系下的投影和子图像合成。该算法避免了逐点插值运算，进一步降低了FFBP算法的计算量。仿真结果表明，该算法能高精度聚焦成像，并且其运算效率相对于基于图像域2维插值的FFBP算法显著提高。
Compared with the Back Projection Algorithm (BPA), the interpolation load of the Fast Factorized Back Projection Algorithm (FFBPA) is released. However, the 2D interpolation in the image domain is essential for the FFBPA and the intensive computational burden limits its application in practice. This paper presents the geometric correction based FFBPA for the spotlight SAR imaging. In this algorithm, the sub-image registration is accomplished by the geometric correction method that the sub-image projection in the different coordinate systems and sub-image fusion are fulfilled by the shift in the range dimension and the rotation in the angle dimension. Thus the method avoids the individual interpolation and it is more efficient than the FFBPA. Simulation results validate its imaging performance and efficiency.
左绍山, 杨泽民, 孙光才, 邢孟道. 基于几何校正的聚束SAR快速分级后投影算法[J]. 电子与信息学报, 2015, 37(6): 1389-1394.
Zuo Shao-shan, Yang Ze-min, Sun Guang-cai, Xing Meng-dao. Geometric Correction Based Fast Factorized Back Projection Algorithm for Spotlight SAR Imaging. JEIT, 2015, 37(6): 1389-1394.
Cumming I G and Wong F H. Digital Processing of Synthetic Aperture Radar Data: Algorithms and Implementation[M]. Norwood, MA: Artech House, 2005: 308-319.
Yang Ze-min, Sun Guang-cai, Wu Yu-feng, et al.. A new fast back projection algorithm based on polar format algorithm [J]. Journal of Electronics & Information Technology, 2014, 36(3): 537-544.
[4]
Ozsoy S and Ergin A. A pencil back projection method for SAR imaging[J]. IEEE Transactions on Image Processing, 2009, 18(3): 573-581.
[5]
Scudder H J. Introduction to computer aided tomography[J]. Proceedings of the IEEE, 1978, 66(6): 628-637.
[6]
Munson D C, Jr O’Brien J D, and Jenkins W K. A tomographic formulation of spotlight mode synthetic aperture radar[J]. Proceedings of the IEEE, 1983, 71(8): 917-925.
[7]
Desai M D and Jenkins W K. Convolution back-projection image reconstruction for spotlight mode synthetic aperture radar[J]. IEEE Transactions on Image Processing, 1992, 1(4): 505-516.
[8]
Wang Yi-duo, Xi Ping, and Xue Wei. Fast filter back projection algorithm based on hexagonal grid[C]. International Conference on Electrical and Control Engineering, Wuhan, China, 2010: 964-969.
[9]
Xiao S, Munson D C Jr, and Basu S. An N2logN back- projection algorithm for SAR image formation[C]. Conference Record of the Thirty-Fourth Asilomar Conference on Signals Systems and Computers, Pacific Grove, CA, USA, 2000, 1: 3-7.
[10]
Yegulalp A F. Fast back-projection algorithm for synthetic aperture radar[C]. The Record of the 1999 IEEE Radar Conference, Waltham, MA, USA, 1999: 60-65.
Chen Si, Zhao Hui-chang, Zhang Shu-ning, et al.. An improved back projection imaging algorithm for dechirped missile-borne SAR[J]. Acta Physica Sinica, 2013, 62(21): 1-9.
[12]
Durand R, Ginolhac G, and Thirion-Lefevre L. Back projection version of subspace detector SAR processors[J]. IEEE Transactions on Aerospace and Electronic Systems, 2011, 47(2): 1489-1497.
Pang Bo, Dai Da-hai, Xing Shi-qi, et al.. Development and perspective of tomographic SAR imaging technique[J]. Systems Engineering and Electronics, 2013, 35(7): 1421-1429.
Zhang Wen-bin, Deng Yun-kai, Wang Yu, et al.. A fast backprojection algorithm for spotlight mode Bi-SAR imaging [J]. Journal of Radars, 2013, 2(3): 357-366.
[15]
Vu V T, Sjogren T K, and Pettersson M I. SAR imaging in ground plane using fast backprojection for mono-and bistatic cases[C]. 2012 IEEE Radar Conference, Atlanta, USA, 2012: 184-189.
[16]
Zhang Lei, Li Hao-lin, and Qiao Zhi-jun. A fast BP algorithm with wavenumber spectrum fusion for high-resolution spotlight SAR imaging[J]. IEEE Geoscience and Remote Sensing Letters, 2014, 11(9): 1460-1464.
Gao Yang, Yu Wei-dong, Feng Jin, et al.. A SAR back projection autofocusing algorithm based on Legendre approximation[J]. Journal of Radars, 2014, 3(2): 176-182.
Zhang Lei, Li Hao-lin, Xing Meng-dao, et al.. Autofocusing the synthetic aperture radar imagery by the fast back- projection algorithm[J]. Journal of Xidian University(Natural Science), 2014, 41(1): 69-74.
[19]
Ulander L M H, Hellsten H, and Stenstrom G. Synthetic- aperture radar processing using fast factorized back- projection[J]. IEEE Transactions on Aerospace Electronic Systems, 2003, 39(3): 760-776.
