This document provides information on a generalized version of the linear spline filter for uniform and non-uniform sampling and the robust spline filters for surface profiles. It supplements ISO 16610‑22, ISO 16610‑30 and ISO 16610‑31.

This document provides information on how to apply the robust estimation to the spline filter as specified in ISO 16610‑22, as well as its generalized form for non-uniform sampling. The weight function chosen for the M-estimator is the Tukey biweight influence function as specified in ISO 16610‑31.