分类： 地球科学 >> 空间物理学 提交时间： 2017-01-04
摘要： A random similarity parameter is proposed which can measure not only the scattering similarity of any two scatterers but also the scattering randomness. The parameter covers both the similarity parameters developed by Yang et al. and Chen et al., and provides a fast and competent alternative to the scattering entropy H parameter. The excellence of the parameter on target discrimination is demonstrated by simply applying it to the terrain classification.
分类： 地球科学 >> 空间物理学 提交时间： 2017-01-04
摘要： A fast offset estimation approach for interferometric synthetic aperture radar (InSAR) image pair subpixel registration is proposed for cases of relatively gentle topography and/or short baseline. A coarse-to-fine registration strategy is taken. The pixel-level offset is estimated in the coarse registration step by a fast feature-based estimation, which uses the speeded up robust feature operator and fast least trimmed squares (Fast-LTS) estimator to accelerate the feature extraction and parameter estimation. A fine registration is performed subsequently. The conventional normalized cross-correlation algorithm (NCCA) searches for the optimal subpixel offset by oversampling either the coarse cross correlation or the InSAR image patch pair. The offset estimation accuracy is restricted by the oversampling rate, and the computational burden is heavy when high accuracy is demanded. In this letter, we transform the oversampling and correlation searching process of NCCA into a nonlinear optimization problem, which takes the maximization of the coherent cross correlation as the objective function; by solving it, the subpixel offset can be fast and exactly obtained without any image oversampling. The final registration parameters are inverted by Fast-LTS fitting of a series of subpixel tie point correspondences which can be constructed after applying the approach to several image patch pairs. RadarSat-2 data are used to test the approach, and the results show that it performs very well not only on the speed but also on the accuracy. �2006 IEEE.
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