Envelope of a signal via Convex hull / Edge detection Is there a method in order to compute some sort of edge detection / convex hull of a signal x[n] (in orange here). Here of course the orange signal is not convex nor concave, but only piecewise...

(I would like to know if this could be an alternative way of computing the envelope of a signal, alternative to the traditional method input -&gt; abs() -&gt; low pass filter)
You can use the Hilbert transform to get the analytic signal.  The absolute value of the analytic signal is the envelope.  It's available in SciPy and many other software suites, though it's usually poorly named.