variable section value give me some mean value but std is zero
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bro i have the same coding in which the db variable section value give me some mean value but std is zero.and also during detection its detect same class (class 1) for all images.please any solution
function [F]=FeatureStatistical(im)
im = double(im(:));
m=mean(mean(im));
s=std(std(im));
F=[m s];
2 个评论
Walter Roberson
2016-11-26
That's odd, I was sure that I had answered this Question, but nothing shows up. Ah well, my answer was the same as dpb's
dpb
2016-11-26
Musta' not gotten saved, Walter--no Answer when I looked first; I sort on "Unanswered" rather than look at other stuff....
采纳的回答
You've double-compensated for the 2D image in
im = double(im(:));
m=mean(mean(im));
s=std(std(im));
im is now a vector; so mean(im) --> single value. mean(value)-->value so the problem doesn't show up here but similarly s=std(std(im)); is taking the std deviation of a single value whose deviation is, in fact, zero.
Rewrite the function as
im = double(im(:));
m=mean(im);
s=std(im);
and all will be well...and just as a minor point since there's no further use in the function for the two temporaries, I'd write it as
F=[mean(im) std(im)];
eliminating them entirely.
1 个评论
Image Analyst
2016-11-26
For 2D images, you can use mean2() and std2(), both in the Image Processing Toolbox.
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