基于综合孔径辐射计稀疏阵列非均匀采样图像的快速重建  

Fast Image Reconstruction for Non-uniform Sampling of Thinned Array of Synthesis Aperture Radiometer

作　　者：孙逢林[1,2] 张升伟[1] 

机构地区：[1]中国科学院微波遥感技术重点实验室中国科学院空间科学与应用研究中心,北京100190 [2]中国科学院研究生院,北京100190

出　　处：《电子与信息学报》2013年第4期927-932,共6页Journal of Electronics & Information Technology

基　　金：国家863计划项目(2007AA120701)资助课题

摘　　要：某些分时采样干涉式微波辐射计成像系统,通常采用稀疏阵列,如圆环稀疏阵列。由于天线阵列优化设计时天线排布位置受限以及天线物理尺寸等限制,具有非均匀空间频域采样的特点。传统的图像重构方法是将非均匀空间频域点插值到均匀的笛卡尔坐标下,补偿空间频率密度,再进行逆快速傅里叶变换。这些插值方法不可避免地会引入误差或者混叠,并且是以假设空间频域的光滑性为前提的,具有局限性。与传统的插值方法不同的是,该文采用最小最大优化准则,先假设图像,再进行共轭梯度迭代快速非均匀傅里叶变换匹配的算法,绕开了空间频域光滑的假设。模拟实验结果表明此算法能够更加快速精确地重建图像。Some thinned array, such as circle thinned array, is used by synthetic aperture interferometric radiometer to realize time-shared sampling, The thinned array may take non-uniform sampling of spatial frequencies due to antenna array structure optimization, the limitation of affined area and the physical size of antenna elements as well. In some traditional image reconstruction methods, non-uniform spatial frequency samplings are usually inserted to uniform Cartesian coordinate. And the spatial frequency densities are compensated. However, as the spatial sampling intensity is assumed to be quite smooth, these methods still bring errors and blurring in spite of different interpolation functions. Moreover, iterative methods that adopted straight Fourier transform are time consuming as they applied to non-uniform spatial frequency samplings. In this paper, another fast interactive image reconstruction method is introduced. The kernel of this algorithm is min-max formulation. The specific procedure of this method is as follows： （1）initiating the image; （2）taking non-uniform fast Fourier transform; （3）operating iterative conjugate gradient matched algorithm. The numerical simulating experiments show that, as spatial frequency samplings density is not smooth, the image can be still reestablished fast and accurately.

关 键 词：稀疏阵列 非均匀快速傅里叶变换 最小最大准则 共轭梯度迭代算法 

分 类 号：TP722.6[自动化与计算机技术—检测技术与自动化装置]