Abstract: A method for registration of image structures is provided which comprises the steps of providing a source image and a target image each comprising a plurality of pixels, wherein each pixels has a gray value, defining at least one gray value level, determining one or more first regions in the source image for each gray value level as confiners, wherein the first region comprises pixels having gray intensities equal to or higher than the gray value level, selecting one of the one or more determined first regions, determining second regions in the target image which are equal to the selected first regions, calculating the mass of each determined second region by forming the sum of the gray intensities of all pixels of the determined second region, and determining the maximum of the calculated masses and selecting the second region having the maximum mass as corresponding to the first region in the target image.