基于NUFFT算法的综合孔径辐射计图像反演方法

An Image Reconstruction Method for Synthetic Aperture Imaging Radiometers Based on NUFFT Algorithm

圆形阵列和旋转阵列排布方式的提出是为进一步降低综合孔径辐射计成像系统的复杂度和成本,然而其缺陷在于过于复杂的亮温图像反演过程,因为该阵列排布方式下的采样样本不是均匀分布于整个采样平面,常规的标准傅里叶变换不能直接运用于此反演过程。提出了一种非标准快速傅里叶变换(NUFFT)算法,用于非均匀采样样本的综合孔径辐射计图像反演计算,该算法结合了高斯栅格算法和对过采样样本的快速傅里叶变换算法,仿真结果表明该算法能够准确地得到反演图像。

In order to further reduce the complexity of synthetic aperture interferometric radiometer imaging system, the circular and rotating array configurations have been proposed. However,these array configurations suffer the extremely complex brightness image reconstruction process. As the sampling data measured by these array configurations are distributed in a non-uniform grid,the conventional cartesian FFT method could not be used directly. This paper presents an Non-uniform Fast Fourier Transform( NUFFT) algorithm for imaging reconstruction of synthetic aperture radiometer. This algorithm relies on a combination of the fast Gaussian gridding algorithm and the use of FFT on an oversampled grid. The numerical simulation results indicate that the proposed algorithm is accurate.