Optical image and SAR image registration based on position constraint

The optical image has high resolution, but it is vulnerable to the adverse environment, resulting in the loss of spectral details. SAR image has strong penetrating power to vegetation, cloud and snow, but it will be interfered by speckle noise. The complementarity of the two images can effectively overcome the limitations of a single image in a complex environment. However, optical image and SAR image have different imaging mechanisms and different gray information, which may lead to the failure of the performance of the two images registration. In order to solve the above problem, in this paper, we propose a method of optical image and SAR image registration based on position constraint. First, the traditional SIFT algorithm is used to register the image coarsely, and then the position of the feature descriptor is locally optimized through the spatial geometric structure characteristics between similar feature points. Experimental results have shown the effectiveness of the proposed method.