A new smoothing spline that acts like a low-pass filter

Abstract Additional weighting factors are introduced into the smoothing spline, proportional to the sampling spacing, in agreement with a mathematicalphysical model for a thin elastic beam at small deflection. This improves the robustness of the spline with respect to variations in spacing of the data. The spline is then shown to correspond to a low pass (long pass) filter. This allows to set the level of smoothing in a more intuitive way, on the basis of the cut-off wavelength.