SAR OCEAN WAVE INVERSION USING IMAGE CROSS SPECTRA

被引:191
作者
ENGEN, G
JOHNSEN, H
机构
[1] NORUT Information Technology
来源
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING | 1995年 / 33卷 / 04期
关键词
D O I
10.1109/36.406690
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
Image cross-spectra obtained by combining pairs of single look SAR images are utilized in an inversion scheme for extracting the underlying ocean wave spectrum. The reasons for proposing the use of image cross-spectra instead of standard multilook spectra are twofold, First, the image cross-spectra are shown to significantly reduce the speckle noise level while preserving the spectral shape, Second, the image cross-spectra provide information about the wave propagation direction. A closed form expression of the ocean-to-SAR spectral transform and its inversion is formulated for the cross-spectral case, The inversion method is based on computing the full derivative of the nonlinear ocean-to-SAR image cross-spectral transform. The SAR image cross-spectra are shown to yield a SNR typically 16-25 dB higher than the corresponding standard 3 look image spectra, The noise level is typically reduced with a factor of 20 compared to the 3 look spectra and a factor of 60 compared to the single look spectra. The inherent information about the wave propagation direction is utilized in the inversion scheme to resolve the 180-degree ambiguity without using any external information, The method is demonstrated on airborne C-band SAR data.
引用
收藏
页码:1047 / 1056
页数:10
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