A fast Gauss filtering algorithm for roughness measurements

A fast and reliable convolution algorithm to calculate the mean line of a roughness profile using the Gaussian filter according to ISO 11562 has been derived. The algorithm is based on a recurrence relation for the weighting function. This greatly speeds up the calculation, making the algorithm nearly comparable to algorithms using the fast Fourier transform (FFT) in a usual way. The algorithm has been implemented as a short C function to be used with any evaluation program. The application of this function to a measured profile is given for demonstration and compared with the results obtained by the ordinary FFT filter algorithm. (C) Elsevier Science Inc., 1996