This part of ISO/TS 16610 specifies spline filters for the filtration of profiles. It specifies in particular how to separate the long and short wave component of a profile.
DS/ISO/TS 16610-22:2007 history
2007DS/ISO/TS 16610-22:2007 Geometrical product specifications (GPS) - Filtration - Part 22: Linear profile filters: Spline filters