FT_DATATYPE_COMP describes the FieldTrip MATLAB structure for comp data
The comp data structure represents time-series channel-level data that has
been decomposed or unmixed from the channel level into its components or
"blind sources", for example using ICA (independent component analysis) or
PCA. This data structure is usually generated with the FT_COMPONENTANALYSIS
function.
An example of a decomposed raw data structure with 100 components that resulted from
a 151-channel MEG recording is shown here:
topo: [151x100 double] the compoment topographies
unmixing: [100x151 double] the compoment unmixing matrix
topolabel: {151x1 cell} the channel labels (e.g. 'MRC13')
label: {100x1 cell} the component labels (e.g. 'runica001')
time: {1x10 cell} the time axis [1*Ntime double] per trial
trial: {1x10 cell} the numeric data [151*Ntime double] per trial
grad: [1x1 struct] information about the sensor array (for EEG it is called elec)
cfg: [1x1 struct] the configuration used by the function that generated this data structure
The only difference to the raw data structure is that the comp structure contains
the additional fields unmixing, topo and topolabel. Besides representing the time
series information as a raw data structure (see FT_DATATYPE_RAW), it is also
possible for time series information to be represented as timelock or freq
structures (see FT_DATATYPE_TIMELOCK or FT_DATATYPE_FREQ).
Required fields:
- unmixing, topo, topolabel
Optional fields:
- cfg, all fields from FT_DATATYPE_RAW, FT_DATATYPE_TIMELOCK or FT_DATATYPE_FREQ
Historical fields:
- offset, fsample
Revision history:
(2014) The combination of comp with raw, timelock or freq has been defined explicitly.
(2011) The unmixing matrix has been added to the component data structure.
(2003) The initial version was defined
See also FT_DATATYPE, FT_DATATYPE_COMP, FT_DATATYPE_DIP, FT_DATATYPE_FREQ,
FT_DATATYPE_MVAR, FT_DATATYPE_RAW, FT_DATATYPE_SOURCE, FT_DATATYPE_SPIKE,
FT_DATATYPE_TIMELOCK, FT_DATATYPE_VOLUME