Re: Mean filter

[Søren Hauberg]

Francesco Potorti` wrote:
> > I'm looking for a *fast* implementation of a mean filter.
>
>
> function m = meanfilter (x, ws)
>     l = length(x);
>     a = cumsum(prepad(x, l+1));
>     b = a(ws+1:l)-a(1:l-ws);
>     m = b/ws;
> endfunction
Thanks, I hadn't thought of that implementation - it's nice :-)
Unforunaly it doesn't appear to be fast enough:

a = rand(1,100000);
f = ones(1,100)/100;

tic; m1 = meanfilter(a, 100); toc
ans = 0.15448

tic; m2 = conv(a, f); toc
ans = 0.12615

Thanks,
Søren



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