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reference:ft_realtime_headlocalizer [2018/08/23 14:43] (current)
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 +=====  FT_REALTIME_HEADLOCALIZER =====
 +
 +Note that this reference documentation is identical to the help that is displayed in MATLAB when you type "help ft_realtime_headlocalizer"​.
 +
 +<​html><​pre>​
 +  <a href=/​reference/​ft_realtime_headlocalizer><​font color=green>​FT_REALTIME_HEADLOCALIZER</​font></​a>​ is a real-time application for online visualization of
 +  the head position for the CTF275 and the Elekta/​Neuromag systems. This uses the
 +  continuous head localization (in CTF terminology,​ i.e. CHL) or position indicator
 +  (in Elekta terminology,​ i.e. cHPI) information.
 + 
 +  Repositioning the subject to a previous recording session can be done by specifying
 +  the previous dataset as cfg.template = '​subject01xxx.ds',​ or by pointing to a text
 +  file created during a previous recording; e.g. cfg.template = '​29-Apr-2013-xxx.txt'​.
 +  The latter textfile is written automatically to disk with each '​Update'​ buttonpress.
 + 
 +  The online visualization shows the displacement of the head relative to the start
 +  of the recording. The timepoint (i.e. position) relative to which the displacement
 +  is shown can be updated can be achieved by marking the HPI at an arbitrary moment
 +  by clicking the '​Update'​ button. This allows for repositioning within a recording
 +  session. Black unfilled markers should appear which indicate the positions of the
 +  coils at the moment of buttonpress. Distance to these marked positions then become
 +  colorcoded, i.e. green, orange, or red.
 + 
 +  Use as
 +    ft_realtime_headlocalizer(cfg)
 +  with the following configuration options
 +    cfg.dataset ​        = string, name or location of a dataset/​buffer (default = '​buffer://​odin:​1972'​)
 +    cfg.template ​       = string, name of a template dataset for between-session repositioning (default = [])
 +    cfg.bufferdata ​     = whether to start on the 'first or '​last'​ data that is available (default = '​last'​)
 +    cfg.xlim ​           = [min max], range in cm to plot (default = [-15 15])
 +    cfg.ylim ​           = [min max], range in cm to plot (default = [-15 15])
 +    cfg.zlim ​           = [min max], range in cm to plot (default is automatic)
 +    cfg.blocksize ​      = number, size of the blocks/​chuncks that are processed (default = 1 second)
 +    cfg.accuracy_green ​ = distance from fiducial coordinate; green when within limits (default = 0.15 cm)
 +    cfg.accuracy_orange = orange when within limits, red when out (default = 0.3 cm)
 +    cfg.dewar ​          = filename or mesh, description of the dewar shape (default is automatic)
 +    cfg.polhemus ​       = filename or mesh, description of the head shape recorded with the Polhemus (default is automatic)
 +    cfg.headshape ​      = filename or mesh, description of the head shape recorded with the Structure Sensor
 + 
 +  The following options only apply to data from the Elekta/​Neuromag system
 +    cfg.headmovement ​   = string, name or location of the .pos file created by MaxFilter which describes the location of the head relative to the dewar
 +    cfg.coilfreq ​       = single number in Hz or list of numbers (default = [293, 307, 314, 321, 328])
 + 
 +  This method is described in Stolk A, Todorovic A, Schoffelen JM, Oostenveld R.
 +  "​Online and offline tools for head movement compensation in MEG."
 +  Neuroimage. 2013 Mar;​68:​39-48. doi: 10.1016/​j.neuroimage.2012.11.047.
 +</​pre></​html>​