Median filters

Syntax: FILTER x f npt
FILTER\MEDIAN x f npt

The default is \MEDIAN, that is, to use a running median filter. The data array, x, is filtered through a window npt points in width. npt must be >2.

The median filter is particularly good at removing 'spikes' from data. The median filter moves a window over the data and outputs the median value of the data points within each window placement. The window butts up against the ends. When npt is even, the filter is applied twice, first skewed left then skewed right, and the results are averaged.

  FILTER command
  Mean filters