<p><span style="padding: 3px 10px; border-radius: 5px; color: #ffffff; font-weight: bold; display: inline-block; background-color: #ff0000;"> External Email - Use Caution </span></p><p></p><div dir="ltr"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div lang="EN-US" style="overflow-wrap: break-word;"><div class="gmail-m_-8957393825310132724WordSection1"><p class="MsoNormal">I would like to find out if there is a manual or if you could point me to literature on the effect of different input parameters in mne.chpi.compute_chpi_head_pos ( info, chpi_locs, dist_limit=0.005, gof_limit=0.98, adjust_dig=False, verbose=None)</p></div></div></blockquote><div><br></div><div>These parameters should behave similarly to how they do in MaxFilter's head position estimation, read more in the MaxFilter manual:</div><div><br></div><div><a href="https://ohba-analysis.github.io/osl-docs/downloads/maxfilter_user_guide.pdf">https://ohba-analysis.github.io/osl-docs/downloads/maxfilter_user_guide.pdf</a></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div lang="EN-US" style="overflow-wrap: break-word;"><div class="gmail-m_-8957393825310132724WordSection1"><p class="MsoNormal">What I am finding is some head position calculations with default goodness of fit (0.98) gives me an empty matrix and a “cannot determine the transformation” error for all coils. While, if I reduce the goodness of fit, or if I set the t_step_max=0.2
(which I am assuming is comparable to Maxfilter -movecomp) for calculation of chpi locations ( mne.chpi.compute_chpi_locs), I do get an head_pos array of a decent size. </p></div></div></blockquote><div><br></div><div>You might need to set `t_window=0.2` as well. If MaxFilter always outputs positions separated by 200 ms, then you might also need `t_step_min=0.2` as well. But there should be some combination of parameters you can use to get the head positions.</div><div><br></div><div>You can also use MaxFilter just for the head position estimation step by calling it with the `-hp some_filename.pos` option, and then use MNE-Python to do the movement compensation using these positions computed by MaxFilter.</div><div><br></div><div>Eric</div><div><br></div></div></div>