Phase flipped dataset


I am very used to the eman school of data processing and would like to flip the phase of the particles before processing. I wonder if it is possible to implement a switch, when switched on, only the absolute values of the CTF is used, instead of signed CTF.


Hi @gepeng1983,

We’ve recorded this in our feature tracker. But for clarification, what are the advantages of phase-flipping first and subsequently using only the absolute values of the CTF?


Hi @gepeng1983 an @apunjani
EMAN uses a different strategy for CTF correction, in which phase flipping the images is the first step. It does not make sense to implement this feature in cryoSPARC, which uses a different strategy for CTF correction.

It is actually convenient for users like me who are used to flip the phase before refinement. Relion also has such an option to suppress CTF signs during CTF correction “–ctf_phase_flipped”. It is actually very easy to implement and doesn’t require any substantial work to the book keeping. Just a switch in the program and a if clause will do it. Thanks.