ctfit

 

a graphical utility for determining CTF parameters directly from data collected on transmission electron microscopes.


Usage
ctfit


Description
Data collected on a transmission electron microscope contains an artifact due to physics of electron optics. This artifact is known as the contrast transfer function, or CTF, of the microscope. In addition, incoherent background noise from multiple sources is present in the images. This utility allows the user to determine the paramters of the CTF in each micrograph by fitting parameters in a predefined 10 parameter model to the power spectrum of data taken from the micrograph. These parameters are then used by the automatic reconstruction procedure to make corrections for the CTF.

In addition to determining the CTF parameters from experimental data, CTFIT can be used to simulate the effects of an electron microscope on simulated data. This can be used as a teaching tool to show what to expect as the microscope focus is changed, for generating simulated data for use in software testing, and to help predict what a specific molecule might look like on the microscope.

EMAN Copyright 1997-8 Steve Ludtke, Phil Baldwin