High-accuracy Registration Method of Solar High-resolution Observation Images and Full-disk Solar Images

In the research of the solar observation, the registration between high-resolution observation images and full-disk solar images is a greatly meaningful work. However, it is difficult to register with high accuracy due to the rotation, scaling and translation between them. This paper presents an image registration method combining local statistical information and control point matching:At first, between the high-resolution observation image and the full-disk solar image parameters are preliminarily estimated about the orientation, scale, and positional parameters. Then the images are pretreated based on the estimated parameters. And then the pretreatment of the field of view is divided into a large number of overlapping local regions equally. Each corresponding local area is determined by the Correlation matching on the full-disk after preprocessing. Next, the sub-pixel offset between each pair of local regions is then measured, and the coordinate positions of the feature point are determined according to the sub-pixel offset between each pair of local regions, which is used as the feature control point in the point matching. Finally, the conversion equations of the affine transformation are established according to the control point, then the least-square method is used to solve the entire field of view of the transformation parameters. The image is reiterated according to the parameters, and the transformation parameters are obtained after the final iteration to register images. By registering the high-resolution observation images and the full-disk Solar SDO/HMI continuous spectrum, the deviation of fitting results is within 0.25 arc-seconds.