DETERMINATION OF MUTUAL ORIENTATION OF IDENTICAL PARTICLES FROM THEIR PROJECTIONS BY THE MOMENTS METHOD

Knowledge of the mutual orientation of the projections is essential for 3D reconstruction. In electron microscopy there are important situations when this orientation is not known a priori. The geometricaly method described elsewhere cannot be used in the important special case of the coaxial projections. The moments method presented here works well in such situations and, together with the geometrical method, compltes the solution of the problem. We describe two variations of the method which are useful in different situations. Together with the theoretical considerations, the algorithms and the results of computer experiments (including data about the influence of noise) are presented. The two-dimensional case is also considered.