星载合成孔径雷达成像斜地校正算法研究

Research for Spaceborne SAR Image's Slant-to-Ground-Range Correction

根据星载合成孔径雷达(SAR)斜地校正模型和校正原理,提出了基于离散傅里叶变换(DFT)的频域sinc插值算法。将SAR图像沿距离向做离散傅里叶变换,在不破坏原信号频谱的条件下,进行频谱中心补0,再做逆傅里叶变换,完成对图像的插值。用该方法对复图像和灰度图像进行斜地校正,证明两种不同图像的sinc插值方法在效果上是一致的,均可完成对能量图像的插值。用Radarsat的数据成像,对复图像、求模图像和量化灰度图像进行频域sinc插值,验证了算法的可行性和有效性。

Based on the model and principle of the spaceborne SAR image's slant-to-ground-range correction, a sinc interpolation algorithm, which can implement slant-to-ground-range correction by DFT in frequency domain, is proposed. After finishing DFT along the cross-track of SAR image, the spectrum is filled with zero in the spectrum center without destroying the original spectra. And then IDFT is adopted to finish the image interpolation. When using the algorithm to implement slant-to-ground-range correction of complex image and gray image, the two application methods are proved to be essentially identical in SAR energy image's interpolation. Finally, based on Radarsat data, the mentioned methods are used in complex image, modular image, and quantified gray image. The results verify the feasibility and validity of the interpolation algorithm.