Fast ISAR Imaging based on High Frequency Scattered Fields from Quadratic Patches

This paper implements the two-dimensional (2D) non-uniform Inverse Fast Fourier Transformation (NUFFT) to Inverse Synthetic Aperture Radar (ISAR) imaging. The complexity of two-dimensional NUFFT is O(MNlog2MN), which is better than direct calculation with complexity O(M2N2) and has controllable interpolation error. As for the echo scattered fields acquisition with respect to multiple frequencies and azimuth angles, we use physical optics (PO) method based on quadratic discretization to reduce the patch number to two orders of magnitude, compared with planar discretization. Three examples prove that the 2D imaging process has nearly equal accuracy and higher efficiency.