The correct reconstruction of the 3D structure from electron micrographs of sets of individual macromolecules or macromolecular assemblies depends crucially on the alignment and orientation determination of the individual images. The lateral alignment from one image to the next is generally easily accomplished by calculating the centre of mass of the individual molecular micrographs. For relatively noise-free pairs of images of unknown structures the sinogram correlation function provides common axes which can determine a correct angular orientation for any set of three images, building consecutively to a complete orientation determination for all images [1]. Low-dose images, however, are inherently noisy. For noisy images the angle determination becomes more problematical, since any fourth noisy image will have three different orientations, each with respect to one of the three possible pairs of three previously oriented noisy images. As more noisy images are added to the set, the number of possible orientations for any given image grow factorially.