[SciPy-Dev] Signal Smooth

[Sturla Molden]

Anne Archibald <archibald at astron.nl> wrote:

> Well, the thing is, signal smoothing is not really a well-defined
> operation.

As you say signal smoothing can mean many things.

Signal smoothing often means using a linear lowpass filter that is
well-behaved in the time domain. Examples are moving average, Gaussian
filter, RC filter (aka single-pole recursive filter), or convolution with a
simple window function (e.g. Hamming or von Hann). A signal smoother is
usually implemented with zero phase (cf. scipy.signal.filtfilt). Signal
smoothing also often means Savitzky-Golay filtering.

Another thing is that we should be careful not to implement things that are
"too simple". It can mean that we are allowing people who don't know what
they are doing to shoot themselves in the leg. Presumably anyone who uses
scipy.signal should know how to smooth a signal or blur an image. Otherwise
there are many excellent textbooks on DSP.

Sturla