Filters in the frequency domain the time series of each voxel in the STC files of an FMR project. Can be used to remove linear and non-linear drifts (high-pass) and/or to smooth the time series (low-pass).
objDocument.TemporalSmoothingFD2D(intHighPass, intLowPass)
Valid only if objDocument
is of type FMR. The high- and low pass values are interpreted in cycles
per lenght of the time course measured in volumes. A high pass value of
"3" removes frequency components below 3 cycles within the time
series. A low pass value equal to or greater than half the length of the
time series will have no effect (Nyquist theorem), i.e. the low-pass filter
is turned off. If the time series data, for example, contains 256 measurements,
then a low pass value of 128 or greater lets everything pass, i.e. it
has no effect and is turned off. In the GUI version, BrainVoyager sets
the default value of the low pass to one-third of the lenght of the time
series which proved to produce good results, i..e. it results in slightly
smoothed time series. It is, however, recommended, not to use low pass
filtering at all when preprocessing data sets from event-related designs.
This is also the reason, why low pass filtering is turned off in the GUI
version (2D Data Preprocessing dialog)
as default.
The resulting filtered data is automatically saved to disk. The names for
the new FMR project and the new STC prefix is determined as in the GUI
version, i.e., if the FMR project "cg_objects.fmr" is used,
the resulting new file on disk will be "cg_objects_pp.fmr".
In addition, a set of new STC files, actuallly containing the time series
data, is stored to disk. If, for example, the prefix in the source FMR
project was "slice-" (referencing file slice-1.stc, slice-2.stc
etc.), the STC prefix of the new FMR file will be "slice_pp-".
If you do not want to use this implicit naming scheme, you might want
to use the method TemporalSmoothingFD2DEx
which allows to specify the name of the resulting FMR project and STC
prefix.
' VBScript
Set doc = BrainVoyager.OpenDocument("cg_objects.fmr")
doc.TemporalSmoothingFD2D 3, 200
// JScript
doc = BrainVoyager.OpenDocument("cg_objects.fmr");
doc.TemporalSmoothingFD2D(3, 200);
#
PerlScript
$doc = $BrainVoyager->OpenDocument("cg_objects.fmr");
$doc->TemporalSmoothingFD2D(3,
200);