one subject different sessions meg coregistration question and oslview question

[ghghgh147]

Dear OHBA group, hello! I run into some problems when I use OSL，I would appreciate it if you could answer it!

question 1

• I have some Elekta Neuromag data which have many subjects, each subject include a few sessions,namely each subject include a few fif files. One subject shares one structure mri. And I noticed that Coregistration is very time-consuming. One fif file is imported for one Meeg object. Now that I have coregistered one meeg object in the subject, do I have to coregister every meeg object in the same subject? Is there any way for meeg objects with coregistration to share coregistration information with meeg objects without coregistration (in the case of a subject sharing a structure MRI), Enabling meeg objects without coregistration to quickly coregister via information sharing? Or am I wrong, so that even though I can do it, I don't get the right result?

question 2

• I have some questions when using oslview, I noticed that when the data was Elekta, oslview only showed megplanar channel type data, why is this, do this only need megplanar waves when checking waveforms and manually marking artifacts, is the megmag channel not used here?
• oslview.m code from line 126, As shown below:

• Set initial channel type
  if any(strcmp(D.chantype,'MEGMAG')) && any(strcmp(D.chantype,'MEGPLANAR')) % ELEKTA
      channel_type = 'MEGPLANAR';
  elseif any(strcmp(D.chantype,'MEGMAG')) % 4D
      channel_type = 'MEGMAG';
  elseif any(strcmp(D.chantype,'MEGGRAD')) % CTF
      channel_type = 'MEGGRAD';
  elseif any(strcmp(D.chantype,'MEG'))
      channel_type = 'MEG';
  else % catch unrecognised case
      channel_type = D.chantype{1};
  end