A demo of Gotcha Large Scene data orthorectified imaging with DEM via Orthorectified Polar Format Algorithm (OPFA)

[1] Hu, Ruizhi, et al. "Orthorectified Polar Format Algorithm for Generalized Spotlight SAR Imaging With DEM." IEEE Transactions on Geoscience and Remote Sensing (2020).
[2] Hu, Ruizhi, et al. "Refocusing and Zoom-In Polar Format Algorithm for Curvilinear Spotlight SAR Imaging on Arbitrary Region of Interest." IEEE Transactions on Geoscience and Remote Sensing 57.10 (2019): 7995-8012
[3] Hu, Ruizhi, et al. "Curvilinear Video-SAR Persistent Imaging with Distortion Correction Based on Nufft-3." IGARSS 2019-2019 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2019

1. DEM_imaging_OPFA_demo.m : main program for DEM imaging
2. getdem.m ： get the DEM for any ROI
3. geotiffread_modified.m : a modified function to read DEM data to avoid error
4. opfaw.m : Imgaing function with DEM (OPFA in [1])
5. opfawo.m : Imgaing function without DEM (RZPFA-3 in [2])
6. db20.m : a simple function to show image in Decibel

1. Gotcha Large Scene data (Disc1.zip and Disc2.zip) are available on https://www.sdms.afrl.af.mil./content/public-data/s3_scripts/index.php?file=GotchaLargeSceneData-Disc1.zip with registration

2. The DEM data "USGS_13_n40w085.tif", avaiable on https://www.sciencebase.gov/catalog/item/5deb329ae4b02caea0f0ea8f (link expired) https://drive.google.com/file/d/1nNERs5p1hNhjOm359Um7jEMKlOGqqTI_/view?usp=sharing

3. NuFFT-3 code in this program is provided on: https://cims.nyu.edu/cmcl/nufft/nufftall-1.3.3.tar.gz

   Mexfile should be built for Matlab to call.

   Please also cite their papers below if you are using their codes.

   • Accelerating the Nonuniform Fast Fourier Transform: (L. Greengard and J.-Y. Lee) SIAM Review 46, 443 (2004).

   • The type 3 nonuniform FFT and its applications: (J.-Y. Lee and L. Greengard) J. Comput. Phys. 206, 1 (2005).

   Other NuFFT-3 schemes are applicable, such as FINUFFT on: https://finufft.readthedocs.io/en/latest/ Quite fast, but tends to crush when data or image is large.

   • Barnett, Alexander H., Jeremy Magland, and Ludvig af Klinteberg. "A Parallel Nonuniform Fast Fourier Transform Library Based on an “Exponential of Semicircle" Kernel." SIAM Journal on Scientific Computing 41.5 (2019): C479-C504.