聚束式SAR中卷积反投影算法的快速实现

对应用于聚束式合成孔径雷达 (SAR) 成像中的卷积反投影 (CBP) 算法进行了详细研究,提出了一种基于傅里叶变换的快速实现方法,使得CBP算法的计算量得到明显降低.在传统的CBP算法中,反投影过程中的重采样通过插值实现,因而所需的插值数量巨大,导致运算效率低下.研究了图像像素之间隐含的相对位置关系之后,本文采用一系列快速傅里叶变换 (FFT)来实现反投影过程中的重采样,避免了运算量巨大的插值过程,故提高了运算效率.仿真结果证明了新算法的可行性和有效性.相比于传统的CBP算法,新算法可以提高大约85%的运算效率.由于FFT适用于并行处理,新方法在实时处理SAR系统中有一定的应用价值.

FAST IMPLEMENTATION OF CONVOLUTION BACKPROJECTION ALGORITHM IN SPOTLIGHT SAR

A fast implementation of the convolution backprojection (CBP) algorithm in spotlight synthetic aperture radar (SAR) is presented based on the fast Fourier transform(FFT). Traditionally, the computation of the 'backprojection' process is expensive, since resampling in the process is implemented by using the interpolation operation. By analyzing the relative location relationship among different pixels, the algorithm realizes the 'backprojection' using a series of FFTs instead of the interpolation operation. The point target simulation validates that the new algorithm accelerates the CBP algorithm, and the computational rate increases about 85%.