Registration parameter spaces for molecular electron tomography images

Abstract

We describe a methodology for exploring the parameter spaces of rigid-body registrations in 3-D. It serves as a tool for guiding and assisting a user in an interactive registration process. An exhaustive search is performed over all positions and rotations of the template, resulting in a 6-D volume, or fitness landscape. This is explored by the user, who selects and views suitable 3-D projections of the data, visualized using volume rendering. The 3-D projections demonstrated here are the maximum and average intensity projections of the rotation parameters and a projection of the rotation parameter for fixed translation parameters. This allows the user to jointly visualize projections of the parameter space, the local behaviour of the similarity score, and the corresponding registration of the two volumes in 3-D space for a chosen point in the parameter space. The procedure is intended to be used with haptic exploration and interaction. We demonstrate the methodology on a synthetic test case and on real molecular electron tomography data using normalized cross correlation as similarity score. © 2011 Springer-Verlag.