tag:blogger.com,1999:blog-1564958057737541664.post8954801851111158190..comments2014-04-13T23:13:33.307-07:00Comments on On Bicycles, and.... what else is there?: SmoothData : a simple Ruby data smoothing classdjconnelhttp://www.blogger.com/profile/01484858820878605035noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-1564958057737541664.post-29736998930514203882012-02-20T07:52:21.161-08:002012-02-20T07:52:21.161-08:00Thanks, Andre! Key issue here is the x-spacing of...Thanks, Andre! Key issue here is the x-spacing of points may be non-uniform. I test the filter by using a cosine function with normally distributed x-spacings and a normal random perturbation applied to y-values. Then I reflect it to make it purely symmetric. I run this through the filter and (1) the result should preserve the symmetry of the original data, (2) there need to be no artifacts associated with the non-uniform spacing in x (the first and second derivatives of the result, not just the smoothed result, should look smooth). This test code is also in <a href="https://docs.google.com/?pli=1#folders/0BwkRBD9gIQRzNmYzZmE4NTAtN2E4MS00YTQ2LTk4OWEtOWFlOTRmYjg2OWJj" rel="nofollow">that Google folder</a>.<br /><br />A challenge with smoothing is how to treat the end-points. I apply a series of two exponential convolutions, one forward, one backward, so the end points get smoothed half as much as the middle, since exponential smoothing in a given direction can't do anything to the first point encountered (unless you assume some value like zero for all points prior, but this fails a translational invariance test).djconnelhttp://www.blogger.com/profile/01484858820878605035noreply@blogger.comtag:blogger.com,1999:blog-1564958057737541664.post-25812370061934038152012-02-20T07:40:11.983-08:002012-02-20T07:40:11.983-08:00Hi,
to smooth out glitches you should check out M...Hi,<br /><br />to smooth out glitches you should check out Median filters/smoothers. They're perfect for that and should be easy to imlement. Keep up the work!andrehttp://www.blogger.com/profile/07472883665118026568noreply@blogger.com