NovaCTF is a freeware for 3D-CTF correction for electron microscopy, as described in this publication:
Turoňová, B., Schur, F.K.M, Wan, W. and Briggs, J.A.G. Efficient 3D-CTF correction for cryo-electron tomography using NovaCTF improves subtomogram averaging resolution to 3.4 Å.
The source code for NovaCTF is distributed under an GPL v.3 license.
For more information how to install and use NovaCTF see Wiki pages.
In case of any problems or if you have feedback for use do not hesitate to write us (or open an issue here).