Patch-based CTF



Where can I get more information about the meaning of plots in the new patch-based CTF job (2.8.0)? Thanks.
PS: I misspoke when I asked about motion correction. That’s clear, but the green vertical lines and ice-thickness plots in patch-based CTF aren’t quite clear. Thanks.


Hi @rbehrouzi, please see this post for more information on Patch CTF.


Thanks @spunjani , but there’s no mention of the relative ice thickness plot and what to read from it, which I couldn’t understand!


Hi Reza,

I am guessing here, but looking at the “relative ice thickness” parameter it seems very similar to the “iciness” parameter introduced in Focus (, and also IIRC from twitter discussions possibly being implemented in the next version of CTFFIND - @spunjani, can you confirm?



Also - if I can add an additional question - what is the meaning of “knots” in the context of Patch CTF and Patch Motion? In context, it seems to mean patches - e.g. Patch CTF defaults to 3 knots in X and 3 in Y - is this more or less correct or is there a more specific meaning? I notice that Patch Motion defaults to 5 knots in Z - does this mean it is using a rolling window of 5 frames and interpolating shifts for the frames within that window?



One more thing - unless I’m missing it, the “relative ice thickness” parameter doesn’t seem to be plottable in the exposure curation job.

This might be a useful parameter to have here, to allow users to easily test the exclusion of icy data.