基于加窗反投影的干涉式微波辐射计成像算法  

The Windowed Back Pro Jection Imaging Method for Interferometric Radiometer

作　　者：张成[1] 吴季[1] 

机构地区：[1]中国科学院空间科学与应用研究中心

出　　处：《电子与信息学报》2008年第5期1064-1067,共4页Journal of Electronics & Information Technology

基　　金：国家自然科学基金(40574070,40671121)资助课题

摘　　要：该文针对旋转扫描干涉式成像系统非均匀采样网格结构,提出了一种加窗反投影算法,通过采样数据进行一维加窗傅里叶变换处理,再反投影到原图像空间来进行图像重建,将二维傅里叶变换转化为一维傅里叶变换和投影变换,避免了空间频域的插值处理。此方法可以对每一个方位的采样数据进行独立处理,实现边采样边处理的成像方式,因此具有很高的成像精度和效率。在此基础上对天线阵采样策略进行分析,得出了角度采样与天线阵基线数之间的平衡关系,为实际应用提供了依据。数值模拟表明了窗函数对噪声抑制和分辨率的影响,通过与其它方法进行比较,进一步验证了此算法的优越性。This paper investigats the imaging theory of the Rotate Scanning Synthetic Aperture Interferometric Radiometer （RS-SAIR） which has a non-Cartesian sampling scheme, and proposes a new imaging algorithm based on windowing back projection. The critical feature of this algorithm is that it takes back projection as the main imaging tool instead of 2-D Cartesian grid Fourier transform, and it involves only 1-D tapered FFT and back projection, which avoids the interpolations from polar sampling grids to Cartesian grids, and could perform imaging and sampling simultaneously, then it leads to a more accurate and fast imaging performance. Being a critical step the windowing effect is analyzed, and different window function is test to show the spatial resolution and noise control of the reconstructed image. Further more, the sampling is analyzed and a rational strategy is achieved. Finally, the imaging of a 2-D scene with a RS-SAIR system is simulated. The comparison of the parameters in the mean square errors and cross correlation coefficient with various methods indicates that the proposed new algorithm is superior to other Cartesian FFT based methods.

关 键 词：综合孔径 干涉被动微波成像 投影变换 加窗反投影 

分 类 号：TP722.6[自动化与计算机技术—检测技术与自动化装置]