-
摘要:
压缩感知(CS)理论在合成孔径雷达(SAR)成像中应用广泛。针对包含城市、河流等区域的非稀疏场景压缩感知SAR成像, 提出基于近似观测模型的混合稀疏表示(MSR)压缩感知SAR成像方法。该方法将复杂的SAR图像分解成点、线、面, 并将线、面分别通过离散余弦变换和曲波变换转换到稀疏域, 使压缩感知的稀疏性条件得以满足, 通过求解基于近似观测模型的二维压缩感知优化问题重建非稀疏场景的SAR图像。所提方法能够实现降采样率条件下对包含城市、河流等非稀疏场景区域的成像, 仿真场景和实测场景成像结果表明了所提方法的有效性。
Abstract:Compressed sensing (CS) theory has been applied in synthetic aperture radar (SAR) in the recent years. A 2-D CS SAR imaging method is proposed using mixed sparse representation (MSR) based on approximate observation model in non-sparse scene compressed sensing SAR imaging. Firstly, non-sparse scene with complicated ground features is decomposed into point-like, edges and smooth components. Then, edges and smooth components are transformed into sparse domain by discrete cosine transform and curvelet transform respectively. And based on approximate observation model, SAR images are derived from 2-D CS optimization problem. Owing to the sparse representation method of non-sparse scene, the proposed method can realize high quality SAR imaging for non-sparse scene. Compared to the existing method, the proposed method has better reconstruction quality for region containing distinct edges and lines, such as city and river. Both the simulation scene and real scene experiments demonstrate the effectiveness of the proposed method.
-
表 1 不同采样率下仿真场景成像结果的RMSE、PSNR、MSSIM
Table 1. RMSE, PSNR, MSSIM of simulation scene SAR images under different downsampling ratio
方法 36%降采样率 64%降采样率 81%降采样率 RMSE PSNR MSSIM RMSE PSNR MSSIM RMSE PSNR MSSIM 基本方法 0.786 -9.268 0.053 0.735 -8.695 0.066 0.503 -5.390 0.109 文献[18]方法 0.316 -1.357 0.181 0.259 0.385 0.219 0.138 5.835 0.365 MSR-CS-SAR方法 0.309 -1.176 0.234 0.206 2.338 0.276 0.111 7.679 0.385 表 2 不同采样率下实测场景成像结果的RMSE、PSNR、MSSIM
Table 2. RMSE, PSNR, MSSIM of real scene SAR images under different downsampling ratio
方法 36%降采样率 64%降采样率 81%降采样率 RMSE PSNR MSSIM RMSE PSNR MSSIM RMSE PSNR MSSIM 基本方法 3.387 7.771 0.142 4.157 5.993 0.173 4.831 4.688 0.174 文献[18]方法 0.180 33.28 0.951 0.099 38.44 0.975 0.093 39.01 0.979 MSR-CS-SAR方法 0.152 34.71 0.950 0.094 38.83 0.978 0.077 40.65 0.985 -
[1] 吴一戎, 洪文, 张冰尘, 等. 稀疏微波成像研究进展[J]. 雷达学报, 2014, 3(4): 383-395. https://www.cnki.com.cn/Article/CJFDTOTAL-LDAX201404002.htmWU Y R, HONG W, ZHANG B C, et al. Current developments of sparse microwave imaging[J]. Journal of Radars, 2014, 3(4): 383-395(in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-LDAX201404002.htm [2] 倪嘉成, 张群, 顾福飞, 等. 基于马尔科夫链的单站SAR海面场景宽幅高分成像算法[J]. 航空学报, 2016, 37(12): 3793-3802. https://www.cnki.com.cn/Article/CJFDTOTAL-HKXB201612024.htmNI J C, ZHANG Q, GU F F, et al. Mono-static SAR HRWS imaging algorithm of sea surface based Markov chain[J]. Acta Aeronautica et Astronautica Sinica, 2016, 37(12): 3793-3802(in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-HKXB201612024.htm [3] DONOHO D. Compressed sensing[J]. IEEE Transactions on Information Theory, 2006, 52(4): 1289-1306. doi: 10.1109/TIT.2006.871582 [4] CANDES E J, WAKIN M B. An introduction to compressive sampling[J]. IEEE Signal Processing Magazine, 2008, 25(2): 21-30. doi: 10.1109/MSP.2007.914731 [5] SAMADI S, CETIN M, MASNADI-SHIRAZI M A. Sparse representation-based synthetic aperture radar imaging[J]. IET Radar Sonar and Navigation, 2009, 5(2): 182-193. [6] FANG J, XU Z B, ZHANG B C, et al. Fast compressed sensing SAR imaging based on approximated observation[J]. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2014, 7(1): 352-363. doi: 10.1109/JSTARS.2013.2263309 [7] 顾福飞, 张群, 杨秋, 等. 基于NCS算子的大斜视SAR压缩感知成像方法[J]. 雷达学报, 2016, 5(1): 16-24. https://www.cnki.com.cn/Article/CJFDTOTAL-LDAX201601004.htmGU F F, ZHANG Q, YANG Q, et al. Compressed sensing imaging algorithm for high-squint SAR based on NCS operator[J]. Journal of Radars, 2016, 5(1): 16-24(in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-LDAX201601004.htm [8] BI H, BI G A, ZHANG B C, et al. From theory to application: Realtime sparse SAR imaging[J]. IEEE Transactions on Geoscience and Remote Sensing, 2020, 58(4): 2928-2936. doi: 10.1109/TGRS.2019.2958067 [9] SHKVARKO Y V, Y ANEZ J I, AMAO J A. Radar/SAR image resolution enhancement via unifying descriptive experiment design regularization and wavelet-domain processing[J]. IEEE Geoscience and Remote Sensing Letters, 2016, 13(2): 152-156. doi: 10.1109/LGRS.2015.2502539 [10] ZHANG C L, LIU Y L, WAN F Y, et al. Multi-faults diagnosis of rolling bearings via adaptive customization of flexible analytical wavelet bases[J]. Chinese Journal of Aeronautics, 2020, 33(2): 407-417. doi: 10.1016/j.cja.2019.03.014 [11] 彭才, 常智, 朱仕军. 基于曲波变换的地震数据去噪方法[J]. 石油勘探, 2008, 47(5): 461-464. https://www.cnki.com.cn/Article/CJFDTOTAL-SYWT200805008.htmPENG C, CHANG Z, ZHU S J. Noise elimination method based on curvelet trans-form[J]. Geophysical Prospecting for Petroleum, 2008, 47(5): 461-464(in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-SYWT200805008.htm [12] CETIN M, STOJANOVIC I, ONHON O, et al. Sparsity-driven synthetic aperture radar imaging: Reconstruction, autofocusing, moving targets and compressed sensing[J]. IEEE Signal Processing Magazine, 2014, 31(4): 27-40. doi: 10.1109/MSP.2014.2312834 [13] SADEGH S, MUJDAT C, MOHAMMAD A M. Multiple feature enhanced SAR imaging using sparsity in combined dictionaries[J]. IEEE Geoscience and Remote Sensing Letters, 2013, 10(4): 821-825. doi: 10.1109/LGRS.2012.2225016 [14] SHEN F F, ZHAO G H, LIU Z C, et al. SAR imaging with structural sparse representation[J]. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2015, 8(8): 3902-3910. doi: 10.1109/JSTARS.2014.2364294 [15] MICHAL A, MICHAEL E, ALFRED B. K-SVD: An algorithm for designing overcomplete dictionaries for sparse representation[J]. IEEE Transactions on Signal Processing, 2006, 54(11): 4311-4322. doi: 10.1109/TSP.2006.881199 [16] 胡长雨, 汪玲, 朱栋强. 结合字典学习技术的ISAR稀疏成像方法[J]. 电子与信息学报, 2019, 41(7): 1735-1742. https://www.cnki.com.cn/Article/CJFDTOTAL-DZYX201907028.htmHU C Y, WANG L, ZHU D Q. Sparse ISAR imaging exploiting dictionary learning[J]. Journal of Electronics & Information Technology, 2019, 41(7): 1735-1742(in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-DZYX201907028.htm [17] LI F, XIN L, GUO Y, et al. A framework of mixed sparse representations for remote sensing images[J]. IEEE Transactions on Geoscience and Remote Sensing, 2017, 55(2): 1210-1221. [18] LI B, LIU F L, ZHOU C B, et al. Mixed sparse representation for approximated observation-based compressed sensing radar imaging[J]. Journal of Applied Remote Sensing, 2018, 12(3): 1-21. [19] DABECHIES I, DEFRISE M, DEMOL C. An iterative thresholding algorithm for linear inverse problems with a sparsity constraint[J]. Communications on Pure and Applied Mathmatics, 2004, 57(11): 1413-1457. [20] RANEY R K, RUNGE H, BAMLER R, et al. Precision SAR processing using chirp scaling[J]. IEEE Transactions on Geoscience and Remote Sensing, 1994, 32(4): 786-799. [21] CANDES E, DEMANET L, DONOHO D. Fast discrete curvelet transforms[J]. Multiscale Modeling & Simulation, 2006, 5(3): 861-899.