<div dir="ltr"><div><div>Dear Rikkert,<br>as far as I know the CTF toolbox is incorporated in the /external directory of FieldTrip and can help you a big deal.<br>If, for example, you recorded or have access to original CTF recordings you can use the readin functions (ft_read_header) to read your datasets.<br>After read-in,you will find that one of the header fields is called 'grad' andin there you have the information of all coils positions.<br>See also this for further reading:<br><a href="http://www.fieldtriptoolbox.org/getting_started/ctf?s[]=ctf">http://www.fieldtriptoolbox.org/getting_started/ctf?s[]=ctf</a><br><br>One of the grad sub-fields is called 'tra' and contains the magnetometers (columns) to gradiometer (rows) weights matrix.<br>If you take care to define a new 'tra' matrix which weights 1 for each magnetometer then you reach your goal.<br>You'll probably need to look into <b><i>grad.coilpos </i></b>and<b><i> </i></b>retain only a subset of your magnetometers positions (either the nearest or the furthest set from the head center)<i>, </i>and take care to keep consistency with the indexes in grad.tra too<i>.<br><br></i></div>IHTH<br></div>Cris<i><br></i><div><div><i><br><br><br></i><div><br><br></div></div></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Aug 24, 2017 at 11:58 AM, HINDRIKS, RIKKERT <span dir="ltr"><<a href="mailto:rikkert.hindriks@upf.edu" target="_blank">rikkert.hindriks@upf.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Dear all,<div><br></div><div>I'm generating simulated data for leadfield matrices for the CTF 275 axial gradiometer system and I would like to compare different the results with </div><div>those obtained from data simulated using a magnetometer configuration. </div><div><br></div><div>It is possible to generate equivalent magnetometer leadfield matrices? </div><div>(Equivalent in the sense of having the same number of coils at the same </div><div>positions).</div><div><br></div><div>Thanks and kind regards,</div><div>Rikkert </div></div><div id="m_-6692326249519774685DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2"><br>
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