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reference:ft_datatype_volume [2018/08/23 14:43]
reference:ft_datatype_volume [2018/08/23 14:43] (current)
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 +=====  FT_DATATYPE_VOLUME =====
 +Note that this reference documentation is identical to the help that is displayed in MATLAB when you type "help ft_datatype_volume"​.
 +  <a href=/​reference/​ft_datatype_volume><​font color=green>​FT_DATATYPE_VOLUME</​font></​a>​ describes the FieldTrip MATLAB structure for volumetric data.
 +  The volume data structure represents data on a regular volumetric
 +  3-D grid, like an anatomical MRI, a functional MRI, etc. It can
 +  also represent a source reconstructed estimate of the activity
 +  measured with MEG. In this case the source reconstruction is estimated
 +  or interpolated on the regular 3-D dipole grid (like a box).
 +  An example volume structure is
 +        anatomy: [181x217x181 double] ​ the numeric data, in this case anatomical information
 +            dim: [181 217 181]         the dimensionality of the 3D volume
 +      transform: [4x4 double] ​         affine transformation matrix for mapping the voxel coordinates to the head coordinate system
 +           unit: '​mm' ​                 geometrical units of the coordinate system
 +       ​coordsys:​ '​ctf' ​                ​description of the coordinate system
 +  Required fields:
 +    - transform, dim
 +  Optional fields:
 +    - anatomy, prob, stat, grey, white, csf, or any other field with dimensions that are consistent with dim
 +    - size, coordsys
 +  Deprecated fields:
 +    - dimord
 +  Obsoleted fields:
 +    - none
 +  Revision history:
 +  (2014) The subfields in the avg and trial fields are now present in the
 +  main structure, e.g. source.avg.pow is now source.pow. Furthermore,​ the
 +  inside is always represented as logical array.
 +  (2012b) Ensure that the anatomy-field (if present) does not contain
 +  infinite values.
 +  (2012) A placeholder 2012 version was created that ensured the axes
 +  of the coordinate system to be right-handed. This actually never
 +  has made it to the default version. An executive decision regarding
 +  this has not been made as far as I (JM) am aware, and probably it's
 +  a more principled approach to keep the handedness free, so don't mess
 +  with it here. However, keep this snippet of code for reference.
 +  (2011) The dimord field was deprecated and we agreed that volume
 +  data should be 3-dimensional and not N-dimensional with arbitary
 +  dimensions. In case time-frequency recolved data has to be represented
 +  on a 3-d grid, the source representation should be used.
 +  (2010) The dimord field was added by some functions, but not by all
 +  (2003) The initial version was defined
 +  See also <a href=/​reference/​ft_datatype><​font color=green>​FT_DATATYPE</​font></​a>,​ <a href=/​reference/​ft_datatype_dip><​font color=green>​FT_DATATYPE_DIP</​font></​a>,​ <a href=/​reference/​ft_datatype_source><​font color=green>​FT_DATATYPE_SOURCE</​font></​a>​