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Hello everyone, I am developing a demo to detect the ripples generated on railway tracks, I would appreciate any help or indication to use this library properly, thanks in advance.

After scanning and obtaining values ​​every 1mm, it is necessary to filter long wave undulations (generated every 1000mm) to center the signal to the axis. I think the roughness analysis like ISO 16610 can be adapted correctly to my needs. You can take the following example image, where I apply a Spline (like https://es.mathworks.com/matlabcentral/fileexchange/52562-surface-metrology-open-profile-spline-filter) or Gaussian filter (like https://es.mathworks.com/matlabcentral/fileexchange/52892-surface-metrology-open-profile-gaussian-filter) with a 1000mm cut-off and I get the red line, which I can use to center the signal on the axis (subtracting this line from the original signal).

I am more focused on the splines and I don't know if the way to operate would be to make multiple splines (every 1m) and then join them, or if the spline function offers a value (windows or cut-off) for what I have described. Also, there are a lot of spline functions and I don't know which is the one indicated for the desired, supposedly cardinal cubic splines.

Please help me, I just came to this forum. I just need that red line to center the signal and to be able to measure wave amplitudes, like distances between peaks.

I would also appreciate if you indicated me to filter outliers.