Spline-Based Image-to-Volume Registration for Three-Dimensional Electron Microscopy
S. Jonić, C.O.S. Sorzano, P. Thévenaz, C. El-Bez, S. De Carlo, M. Unser
Ultramicroscopy, vol. 103, no. 4, pp. 303–317, July 2005.
This paper presents an algorithm based on a continuous framework for a posteriori angular and translational assignment in three-dimensional electron microscopy (3DEM) of single particles. Our algorithm can be used advantageously to refine the assignment of standard quantized-parameter methods by registering the images to a reference 3D particle model. We achieve the registration by employing a gradient-based iterative minimization of a least-squares measure of dissimilarity between an image and a projection of the volume in the Fourier transform (FT) domain. We compute the FT of the projection using the central-slice theorem (CST). To compute the gradient accurately, we take advantage of a cubic B-spline model of the data in the frequency domain. To improve the robustness of the algorithm, we weight the cost function in the FT domain and apply a “mixed” strategy for the assignment based on the minimum value of the cost function at registration for several different initializations. We validate our algorithm in a fully controlled simulation environment. We show that the mixed strategy improves the assignment accuracy; on our data, the quality of the angular and translational assignment was better than 2 voxel (i.e., 6.54 Å). We also test the performance of our algorithm on real EM data. We conclude that our algorithm outperforms a standard projection-matching refinement in terms of both consistency of 3D reconstructions and speed.
@ARTICLE(http://bigwww.epfl.ch/publications/jonic0502.html, AUTHOR="Joni{\'{c}}, S. and S{\'{a}}nchez Sorzano, C.{\'{O}}. and Th{\'{e}}venaz, P. and El-Bez, C. and De Carlo, S. and Unser, M.", TITLE="Spline-Based Image-to-Volume Registration for Three-Dimensional Electron Microscopy", JOURNAL="Ultramicroscopy", YEAR="2005", volume="103", number="4", pages="303--317", month="July", note="")