Reading a CTF file without HPI coils

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1

Hello. I am trying to analyse a pilot study’s recording of MEG data I made a couple of days ago. We have a CTF machine in our research center. It is the first time I have done the MEG recording so I was more focused on debugging my script and perhaps have not done all the necessary things. In particular no HPI coils were used.

Now I am trying to open the resulting recording file and when I try to use mne.io.read_raw_ctf I have an error: “HPI information not available”.

I have tried to look in the source code of this function and apparently coil information is used quite a lot so I can not just set it to None or something like that. Is there a way a circumvent it and open the CTF file without coil info nevertheless, to check the basic recording quality?

2

Okay, I think I have found a solution. The problem was due to the fact that one of the .ds files we got was not only very short but also corrupted. In particular, the .hc file contained only the following two strings “Unable to make head coil file.
Reason: no data in this DataSet.”.

When I just delete this last data set, things work