SAR image registration combining watershed segmentation and mutual information
Xiangyu Yu, Hong Sun, Yongfeng Cao · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2005
A registration method combining watershed segmentation and mutual information for Synthetic Aperture Radar(SAR) images is introduced in this paper. In this approach, the gradient images of SAR are first segmented by morphological watershed algorithm. Oversegmentation is diminished by basin dynamics. Mutual information is calculated on a pair of segmentation results. The maximum of the mutual information indicates the optimal matching parameters. In order to avoid falling into local optimal, a two-step modification is also proposed. Coarse parameters are obtained on the segmentation result containing a small number of regions, and refinement is done at the neighbour of the coarse matching with more regions in segmentation. The optimal matching at the second step indicates the final registration parameters. Experiments on multi-polarization SAR images show that this approach has evident effect for registration of SAR images with rigid or small geometrical difference.