For a NIFTI .img file the periodogram of the time series are divided by a flat spectral estimate using the median periodogram ordinate. The resulting values are then combined within each Fourier frequency and quantiles are plotted against frequency. This provides a fast look at a fMRI dataset to identify any artifacts that reside at single frequencies.
f.spectral.summary.nifti(file, mask.file, ret.flag = FALSE, verbose = TRUE)If ret.flag = TRUE the an array of quantiles at each
frequency is returned
file The location of .img file
mask.file Optional location of a .img file
containing a mask. If not given then one is created.
ret.flag flag specifying whether to return the
array of quantiles at each frequency
verbose logical to display information on the progress of computations
f.nifti.file.summary