1. A method for registering two three-dimensional (3D) volumes, the method comprising; projecting the two 3D volumes in a plurality of two-dimensional (2D) spaces; estimating a plurality of two dimensional (2D) deformable fields for a corresponding 2D space; backprojecting the 2D deformation fields in a 3D space; updating a three dimensional (3D) deformable field, wherein updating the 3D deformable field comprises composition of backprojections of the 2D deformable fields in a plurality of projection directions.