Send to:

Choose Destination
See comment in PubMed Commons below
Ultramicroscopy. 2002 Jul;92(2):33-46.

Efficiency of 2D alignment methods.

Author information

  • 1Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, 77030, USA.


In single particle analysis, the alignment of two-dimensional images is a fundamental step aimed at bringing into register various particle views of biological macromolecules observed with the electron microscope. The computational efficiency of this step is a deciding factor in design of alignment strategies for large sets of noisy data and in development of three-dimensional structure refinement methods. In addition, the accuracy of the alignment method varies depending on the numerical solutions adopted to efficiently perform exhaustive searches for three orientation parameters. The selected alignment methods are analyzed in terms of their computational complexity and the estimates of numbers of arithmetic operations for each method are given. The tests of alignment accuracy are performed using images simulated in accordance with the linear theory of image formation in the electron microscope. It is demonstrated that the efficiency of the alignment methods can be improved if approximate centers of gravity of particle views are known. The accuracy of the methods considered is largely affected, particularly for high noise levels, by the order in which interpolation steps are applied.

[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Write to the Help Desk