title: Defocus estimation from stroboscopic cryo-electron microscopy data.
abstract: Defocus estimation is an important step for improving the resolution of single particle reconstructions. It can be troublesome to estimate the defocus from low-dose cryo-electron microscopy (cryo-EM) data, particularly if there is not sufficient contrast present in the Fourier transform of the micrograph. Most existing approaches estimate the defocus from the presence of Thon rings within the power spectrum, employing image enhancement techniques to highlight these rings. In this paper, an approach to estimating the defocus from a stroboscopic image series is described. The image series is used to obtain two statistical metrics: figure of merit (FOM) and Q-factor. These metrics have been used to estimate the defoci from low-dose stroboscopic cryo-EM data consisting of a variable number of images.
authors.affiliation: Department of Molecular Cell Biology, Leiden University Medical Center, P.O. Box 9600, 2300RC Leiden, The Netherlands.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Karimi Nejadasl
authors.forename: Manikandan
authors.initials: M
authors.lastname: Karuppasamy
authors.forename: Abraham J
authors.initials: AJ
authors.lastname: Koster
authors.forename: Raimond B G
authors.initials: RB
authors.lastname: Ravelli
mesh_terms: D000818:Animals; D020285:Cryoelectron Microscopy / Q000379:methods*; D006454:Hemoglobins / Q000737:chemistry; D009835:Oligochaeta / Q000737:chemistry
chemical_list: D006454:Hemoglobins