The Windowed Back Pro Jection Imaging Method for Interferometric Radiometer
Zhang Cheng①②; Wu Ji①
①Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100080, China; ②Graduate University of Chinese Academy of Sciences, Beijing 100039, China
Abstract：This paper investigats the imaging theory of the Rotate Scanning Synthetic Aperture Interferometric Radiometer (RS-SAIR) which has a non-Cartesian sampling scheme, and proposes a new imaging algorithm based on windowing back projection. The critical feature of this algorithm is that it takes back projection as the main imaging tool instead of 2-D Cartesian grid Fourier transform, and it involves only 1-D tapered FFT and back projection, which avoids the interpolations from polar sampling grids to Cartesian grids, and could perform imaging and sampling simultaneously, then it leads to a more accurate and fast imaging performance. Being a critical step the windowing effect is analyzed, and different window function is test to show the spatial resolution and noise control of the reconstructed image. Further more, the sampling is analyzed and a rational strategy is achieved. Finally, the imaging of a 2-D scene with a RS-SAIR system is simulated. The comparison of the parameters in the mean square errors and cross correlation coefficient with various methods indicates that the proposed new algorithm is superior to other Cartesian FFT based methods.
2008, Vol. 30 
