Sorzano, C. O. S.; Jonic, S.; El-Bez, C.; Carazo, J. M.; De Carlo, S.; Thévenaz, P. & Unser, M. A multiresolution approach to pose assignment in 3-D electron microscopy of single particles J. Structural Biology, 2004, 146, 381-392
Three-dimensional (3D) electron microscopy (3DEM) aims at the determination of the spatial distribution of the Coulomb potential of macromolecular complexes. The 3D reconstruction of a macromolecule using single-particle techniques involves thousands of 2D projections. One of the key parameters required to perform such a 3D reconstruction is the orientation of each projection image as well as its in-plane orientation. This information is unknown experimentally and must be determined using image-processing techniques. We propose the use of wavelets to match the experimental projections with those obtained from a reference 3D model. The wavelet decomposition of the projection images provides a framework for a multiscale matching algorithm in which speed and robustness to noise are gained. Furthermore, this multiresolution approach is combined with a novel orientation selection strategy. Results obtained from computer simulations as well as experimental data encourage the use of this approach.
Angular assignment, wavelets, multiresolution, heuristics