Iterative/robust StdDev calculations are used both for fitting the piece-wise polynomial to the averaged data, and when using it to flag the un-averaged data.
These flags form the output of the TFCrop algorithm.
– There are additional outlier-detection options.
(1) usewindowstats = 'sum' is an approximation to the sumThreshold method used at LOFAR.
(2) usewindowstats = 'std' is an approximation to the 'rflag' method in AIPS.
Both these methods are experimental.