Insufficiently sensitive head movement detection for chpi extraction?

[kinleyid]

When extracting continuous head position from CTF systems, np.all in the following line:

mne-python/mne/chpi.py

Line 237 in d74cc20

indices.extend(np.where(np.all(np.diff(chpi_data, axis=1), axis=0))[0] + 1)

appears to require that every coordinate of every HPI coil changes from sample to sample for any head movement to be detected. I noticed this because I have a number of participants for whom no head movement is detected over 10 minute runs, which seems too good to be true (and indeed, the HPI coil positions do change for these participants, but not dramatically enough to be detected with the above-referenced code). It seems like using np.any would fix this issue.

[welcome]

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