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From: | Quentin Spencer |
Subject: | Re: Mean filter |
Date: | Thu, 21 Jul 2005 08:57:48 -0500 |
User-agent: | Mozilla Thunderbird 1.0.6-1.1.fc4 (X11/20050720) |
Søren Hauberg wrote:
Robert A. Macy wrote:Was that the first time you ran meanfilter? Doesn't the second time run faster?No that was the third time.In the test below I cheated a little bit and created the filter (f) before I called tic, so this will also affect time.Thanks, SørenThanks, 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
I tried this with both the filter and conv functions, with similar results (though filter seemed very slightly faster). Since they are precompiled functions, I think the only way you could improve on them is to write your own precompiled function that does only addition and no multiplication--you could scale the results afterward if you needed to.
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