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reference:ft_resampledata [2018/08/23 14:43] (current)
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 +=====  FT_RESAMPLEDATA =====
 +Note that this reference documentation is identical to the help that is displayed in MATLAB when you type "help ft_resampledata"​.
 +  <a href=/​reference/​ft_resampledata><​font color=green>​FT_RESAMPLEDATA</​font></​a>​ performs a resampling or downsampling of the data
 +  Use as
 +    [data] = ft_resampledata(cfg,​ data)
 +  The data should be organised in a structure as obtained from
 +  the <a href=/​reference/​ft_preprocessing><​font color=green>​FT_PREPROCESSING</​font></​a>​ function. The configuration should contain
 +    cfg.resamplefs ​     = frequency at which the data will be resampled (default = 256 Hz)
 +    cfg.detrend ​        = '​no'​ or '​yes',​ detrend the data prior to resampling (no default specified, see below)
 +    cfg.demean ​         = '​no'​ or '​yes',​ whether to apply baseline correction (default = '​no'​)
 +    cfg.baselinewindow ​ = [begin end] in seconds, the default is the complete trial (default = '​all'​)
 +    cfg.feedback ​       = '​no',​ '​text',​ '​textbar',​ '​gui'​ (default = '​text'​)
 +    cfg.trials ​         = '​all'​ or a selection given as a 1xN vector (default = '​all'​)
 +    cfg.sampleindex ​    = '​no'​ or '​yes',​ add a channel with the original sample indices (default = '​no'​)
 +  Instead of specifying cfg.resamplefs,​ you can also specify a time axis on
 +  which you want the data to be resampled. This is usefull for merging data
 +  from two acquisition devides, after resampledata you can call <a href=/​reference/​ft_appenddata><​font color=green>​FT_APPENDDATA</​font></​a>​
 +  to concatenate the channles from the different acquisition devices.
 +    cfg.time ​       = cell-array with one time axis per trial (i.e. from another dataset)
 +    cfg.method ​     = interpolation method, see INTERP1 (default = '​pchip'​)
 +  Previously this function used to detrend the data by default. The
 +  motivation for this is that the data is filtered prior to resampling
 +  to avoid aliassing and detrending prevents occasional edge artifacts
 +  of the filters. Detrending is fine for removing slow drifts in data
 +  priot to frequency analysis, but detrending is not good if you
 +  subsequenlty want to look at the evoked fields. Therefore the old
 +  default value '​yes'​ has been removed. You now explicitely have to
 +  specify whether you want to detrend (probably so if you want to
 +  keep your analysis compatible with previous analyses that you did),
 +  or if you do not want to detrent (recommended in most cases).
 +  If you observe edge artifacts after detrending, it is recommended
 +  to apply a baseline correction to the data.
 +  The following fields in the structure '​data'​ are modified by this function
 +    data.fsample
 +    data.trial
 +    data.time
 +  To facilitate data-handling and distributed computing you can use
 +    cfg.inputfile ​  ​= ​ ...
 +    cfg.outputfile ​ =  ...
 +  If you specify one of these (or both) the input data will be read from a *.mat
 +  file on disk and/or the output data will be written to a *.mat file. These mat
 +  files should contain only a single variable, corresponding with the
 +  input/​output structure.
 +  See also <a href=/​reference/​ft_preprocessing><​font color=green>​FT_PREPROCESSING</​font></​a>,​ RESAMPLE, DOWNSAMPLE, INTERP1