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”.
FT_DATATYPE_VOLUME 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 FT_DATATYPE, FT_DATATYPE_DIP, FT_DATATYPE_SOURCE