An accurate 2-D nonuniform fast fourier transform method applied to high resolution SAR image reconstruction

Abstract

We present a new method to reconstruct high resolution SAR images. When the far-field data arranged in the polar format, a 2-D Fourier transform can achieve the image reconstruction. But the data do not fall on a Cartesian grid, we introduce 2-D Nonuniform Fast Fourier Transform (NUFFT) to reconstruct the SAR image directly. It is the first time to use NUFFT technology in SAR image reconstruction. Instead of interpolating the input data, NUFFT interpolate the exponential function for each sampling point. The technology could easily extended to high dimensional by tensor product. The 2-D NUFFT is very suitable to reconstruct SAR image. A ground target example will shown to demonstrate that the reconstructed images have higher resolution than the general method when using the same data.

Focusing Translational Variant Bistatic Forward-Looking Sar Data Based on Two-Dimensional Non-Uniform FFT

“…After mapping operation, the data from (f τ , f η ) space to (f τ , f η ) space, (19) can be converted to…”

“…Obviously, the data utilization is quite low, which affects the image performance severely. NUFFT is an accurate and efficient technique to evaluate the non-uniform discrete Fourier transform (NUDFT) [19][20][21][22][23]. According to [20], the reconstruction of target scattering function can be represented by…”

“…For the range-variant term, it adopts 2-D Stolt interpolation to correct the nonlinear dependence on the range and azimuth frequencies. 2-D Stolt interpolation transforms the non-uniform frequency domain into a regular spaced rectangle [18,19]. For TV mode, the imaging block size becomes very small, leading low utilization of the collected data in the spatial frequency domain.…”

“…Non-uniform FFT (NUFFT) is an accurate and efficient technique to evaluate the non-uniform discrete Fourier transform (NUDFT) [19][20][21][22][23]. Recently, NUFFT technique was introduced to the research field of SAR data processing [19,21,22].…”

“…Recently, NUFFT technique was introduced to the research field of SAR data processing [19,21,22]. In this paper, a novel Omega-K algorithm based on 2-D NUFFT for TV-BFSAR imaging is proposed.…”