A multi-stage astronomical images registration based on nonsubsampled contourlet transform

In order to align the astronomical images with the characteristics of serious noise and smoothing edges, we propose an astronomical image registration based on the nonsubsampled contourlet transform (NSCT) and a new evaluation criterion to estimate the results of the registration. The registration algorithm includes coarse registration and fine registration. According to the shift-invariance of the NSCT, the approximate translations, which will be used to create the search windows of the fine registration, are obtained. Next, the local searches are operated in subband images, and then the feature points, which are extracted by using NSCT coefficients, are matched by utility of the gray correlation, and finally we can calculate the transformation parameters. The preliminary experimental results demonstrate the robustness and efficiency of the proposed algorithm in the noise suppression and the high registration accuracy which can achieve 0.2 pixels.