CTF reading routines now GPL

[Robert Oostenveld]

> I write in reference to the 2 script files you sent us, read_ctf_res4
> & read_ctf_meg4. In read_ctf_res4, lines 230-234 & 254-258 apparently
> correct for some mis-oriented sensors. The question is whether it
> holds true for all CTF installations or simply the one at Donders?
> Would appreciate a clarification on this point.  Thanks.

Hi Hiren,

No, it is not specific for the FCDC system. The res4 files of the 275
channel CTF system installed at the NIH also requires that the coil
orientation of some (~130 of the 275) MEG sensors have to be flipped.

Note that it does not affect the recorded data, but only the forward
computed model-data in FieldTrip. I don't know how it is handeled in
the CTF dipolefitting or SAM software itself, perhaps there is also a
flag in the res4 header which I am not aware of that indicates whether
the coil orientation is flipped.

Robert