frenet_robust.zip

This is a robust estimation of curvature, torsion, and the Frenet frame of a space curve. It works well even when data points are noisy. It uses the geometric definition of curvature as the inverse radius of an osculating circle that kisses the curve. Torsion is determined from the rotation of the osculating plane. The user can choose the level of regularization of torsion by setting a non-zero weight. A demo script presents several examples, including curves with inflection points, where the Frenet frame is ill-defined.