SAR and visible image registration method-based on edge and SURF algorithm

Due to the prominent difference of the imaging mechanism between visible and synthetic aperture radar (SAR) images, it is very difficult to extract common features and register, but in some cases, the edges of these two kinds of images have some certain correlation. According to the above problem, an image registration algorithm based on edge and speed-up robust feature (SURF) is proposed. Firstly, the similarity of these two images is enhanced through appropriately preprocessing, the common edge features are extracted by Canny operator which has good performance, and the SURFs are extracted from the edges of the images; then the features matching is done by the ratio purification method, the random sample consensus (RANSAC) algorithm is applied to remove the false matching points, and the affine transformation model is calculated to realize image automatic registration of SAR and visible image. Experimental results demonstrate that the correct matching probability of the proposed algorithm is 100% and the root mean square error is 0.852 pixel, moreover, the registration accuracy can achieve sub-pixel level,which proves the validity of the algorithm.