| 摘要: |
| 针对合成孔径雷达(Synthetic Aperture Radar,SAR图像易受环境噪声影响，导致目标处信噪比降低的问题，提出了将奇异值分解(Singular Value Decomposition,SVD和最小熵反褶积(Minimum Entropy Deconvolution,MED结合并用于改进后向投影(Back-Projection,BP的方法。首先，将实测采集的回波信号进行奇异值分解得到奇异值矩阵，只保留前5个奇异值后重构回波信号矩阵实现初步降噪。然后再将信号进行最小熵反褶积滤波处理，通过利用信号不断迭代更新滤波器的系数最小化信号的熵，以使输出信号的峰度最小化从而实现噪声抑制。再利用零相位滤波器(Zero-Phase Filter,ZPF对信号进行滤波恢复信号的相位延迟。最后，利用后向投影算法得到SAR图像。实验结果证明，该方法使得大小两个角反射器的信噪比分别提升了7.9 dB和9.1 dB，显著提高了SAR图像中目标处的信噪比。 |
| 关键词: 合成孔径雷达(SAR 后向投影 奇异值分解 最小熵反褶积(MED 零相位滤波器(ZPF |
| DOI：10.20079/j.issn.1001-893x.240707001 |
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| 基金项目:国家自然科学基金资助项目(62101085 |
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| An Improved Back Projection Method Based on Singular Value Decomposition and Minimum Entropy Deconvolution |
| NIU Yan,NIE Wei,ZHOU Mu,YANG Xiaolong |
| (School of Communications and Information Engineering,Chongqing University of Posts and Telecommunications,Chongqing 400065,China) |
| Abstract: |
| To address the issue of synthetic aperture radar(SAR images being susceptible to environmental noise,which leads to a reduction in the signal-to-noise ratio(SNR at target locations,a method integrating singular value decomposition(SVD and minimum entropy deconvolution(MED to enhance the Back Projection(BP algorithm is proposed.Initially,the acquired echo signals undergo SVD,and a singular value matrix is obtained.By retaining only the first five singular values and reconstructing the echo signal matrix,an initial noise reduction is achieved.Subsequently,the signals are processed using MED filtering,where filter coefficients are iteratively updated to minimize the entropy of the signal,thereby reducing the kurtosis of the output signal and suppressing noise.A Zero-Phase Filter(ZPF is then applied to restore any phase delays.Finally,the SAR image is generated using the BP algorithm.Experimental results demonstrate that this method significantly enhances the SNR at target locations,with improvements of 7.9 dB and 9.1 dB for large and small corner reflectors,respectively. |
| Key words: synthetic aperture radar(SAR back projection singular value decomposition minimum entropy deconvolution(MED zero-phase filter(ZPF |
