Hello,
Le 24/04/2015 14:05, [email protected] a écrit :
Dear All,
I am absolutly not familiar with "signal processing" field, so my question is
probably naïve: how can I proceed to get the envelop curve (maximum values) of a non
periodic noisy signal ?
Here is an example and its result:
x = linspace(0,20,300);
y = exp((2-x)/5).*sin(x)+rand(x);
clf
plot2d(x,y)
e = gce();
e = e.children;
e.foreground = color("grey80");
d = diff(y) ./ diff(x);
pmax = find(d(1:$-1)>=0 & d(2:$)<0)+1;
pmin = find(d(1:$-1)<0 & d(2:$)>0)+1;
// edges corrections
if d(1)<0 then
pmax = [1 pmax]
end
if d($)<0 then
pmin = [pmin length(y)]
end
//
plot(x(pmax),y(pmax),"r",x(pmin),y(pmin),"b")
Zooming on that shows in some places the limits of this naive approach,
to be refine.
Regards
Samuel
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